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1 Range Cattle Research and Education Center March 2011 Research Report RC 20 1 1 1 CLIMATOLOGICAL REPORT 20 10 Range Cattle Research and Education Center Brent Sellers and Reyna Speckmann Weather conditions strongly influence agricult ural operations from planting through harvesting. Knowledge of annual rainfall and temperature cycles along with their extremes help producers determine optimum times to prepare and plant seedbeds, fertilize pastures, apply herbicides, control water, an d supplement cattle on pasture or range. Weather conditions influence seed germination, forage growth, palatability, and nutritive value. This research report presents a summary of rainfall, air temperature, evapotranspiration, and solar radiation for 2010 obtained at the Range Cattle Research and Education Center (REC) Ona, Florida, and is compared to a 6 9 year summary of rainfall data and a 68 year summary of temperature data collected from this location. The center is located 81o 5 6.406' W and 27o 23.733 N in south central Florida approximately 45 miles (72 km) east of the Gulf of Mexico and 100 miles (160 km) west of the Atlantic Ocean. Weather observations were collected with a Weather Watch 2000 (Campbell Scientific, Inc) from 1997 until 2005. Beginning in 2006, observations were collected using the Florida Automated Weather Network (FAWN). Accuracy of rainfall as measured by the Weather Watch 2000 or FAWN and was verified by comparing with rainfall measured using US Weather Service standard gauge. Measurements reported prior to 2006 were recorded at 0900 h ; thus data on a given day represent ed the previous 24hour period. Beginning in 2006, measurements were recorded for an entire 24h period beginning at midnight. Rainfall Annual rainfall for 20 10 totaled 49.15 inches (Table 1) which was 4.41 inches ( 8.2 %) l ess than the 6 9 year average of 5 3. 56 inches (Table 1) The lowest annual total was observed in 2000 when 32.02 inches were measured, and the greatest annual rainfall total on recor d was in 1959 when 78.82 inches were recorded. Characterized by a particularly wet spring, 2010 m onthly rainfall totals exceeded the 69 year average for March, April, May, August, and November (Figure 1; Table 1) Rainfall deficits exceeding two inches were recorded in June, July, September, and

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2 October Above normal spring rainfall provided some growth of forages for hay, resulting in a fairly good hay crop. D aily rain fall equaled or exceeded 1 inch on 20 separate occasions in 20 10. Four of these rain event s exceeded 2 inches (Table 2). The single greatest daily rain event was 1 August when 3.20 inches were recorded. Table 1. Summary of rainfall by months. Range Cattle REC, 2010. 1942 to 20 10 2010 Month Maximum / month Minimum / month 6 9 year average Total Difference from 6 9 year average -------------------------------------------inches ----------------------------------------January 8.45 0.03 2.1 2 2.02 0. 10 February 9.59 0.02 2.58 2.48 0.10 March 12.34 0.13 3. 12 5.94 2.82 A pril 11.91 0.00 2.4 8 2.88 0.40 May 10.58 0.00 3. 80 6.28 2. 48 June 18.99 2.79 8.6 2 4.65 3.97 July 19.74 1.87 8.3 2 5.74 2.58 August 16.10 3.13 8.3 9 11.95 3.56 September 20.11 1.14 7.2 3 3.60 3. 63 October 11.2 3 0.0 0 2.97 0. 00 2. 97 November 11.22 0.0 7 1.9 1 2.77 0.86 December 8.61 0.16 2.0 2 0.84 1.18 Year total 53. 56 4 9.15 4.41 *Inches x 2.54 = cm. Since rainfall records began in July 1942, means for January to June are 68 y ear means Evapo transpiration Evapotranspiration is the total am ount of water transferred from the earth to the atmosphere. Evapotranspiration exceeded rainfall in April, June, September, October, and December during 2010 (Figure 2). Evapotranspiration generally exceeds rainfall in January to May and October to Dec ember, which are months with limited rainfall. R ainfall exceeded evapotranspiration by 5.82 inches for the entire year.

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3 Table 2. Daily maximum and minimum temperature, preci pitation, and solar radiation for 2010, Range Cattle REC. January February March April Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/ Day o F o F inches m 2 o F o F inch es m 2 o F o F inches m 2 o F o F inches m 2 1 66.4 47.25 0.99 2.742 64.98 51.57 0.05 2.957 72.48 36.41 0 .00 25.81 82.38 49.60 0 .00 27.80 2 59.2 38.64 0 .00 11.45 69.73 54.18 0.06 3.552 73.31 43.85 0.12 11.79 83.05 54.32 0 .00 28.34 3 45.99 36.58 0 .00 5.402 65.2 8 52.23 0 .00 13.79 57.22 39.19 0 .00 16.09 85.21 54.07 0 .00 25.21 4 54.81 31.60 0 .00 11.10 77.47 50.13 0 .00 16.86 58.15 35.29 0 .00 26.70 54.25 55.96 0 .00 28.19 5 49.37 29.46 0 .00 10.58 78.64 61.21 1.03 5.418 63.63 32.65 0 .00 26.71 83.61 56.77 0 .00 28.58 6 52.27 28.12 0 .00 11.14 67.53 55.04 0 .00 15.43 67.35 34.80 0 .00 27.37 82.89 56.64 0 .00 28.38 7 62.11 26.79 0 .00 11.44 59.14 41.03 0 .00 16.72 71.58 33.72 0 .00 27.75 84.42 54.52 0 .00 27.05 8 68.9 35.36 0 .00 6.755 64.83 37.09 0 .00 16.56 74.23 38.38 0 .00 2. 540 83.75 61.12 0 .00 20.06 9 46.67 30.27 0.31 2.173 72.79 49.73 0.06 6.668 74.11 45.63 0 .00 1.439 78.64 67.98 0.01 16.69 10 46.31 28.51 0 .00 10.59 59.02 42.17 0 .00 23.04 80.28 49.86 0 .00 20.57 82.35 58.93 0 .00 25.83 11 54.07 25.15 0 .00 11.36 59.86 36.98 0 .00 19.79 80.94 63.36 0.03 7.680 80.87 63.23 0 .00 15.36 12 62.6 24.57 0.04 11.46 59.65 47.07 1.02 2.462 66.58 61.57 2.46 2.091 81.95 61.27 0 .00 24.53 13 63.27 29.84 0 .00 18.54 54.03 63.72 0 .00 14.27 71.08 54.09 0 .00 26.34 84.16 60.96 0 .00 26.89 14 71. 82 38.56 0 .00 17.59 57.16 33.58 0 .00 16.11 71.10 51.87 0 .00 23.58 81.54 60.46 0 .00 29.16 15 77 49.10 0 .00 14.56 71.64 34.28 0 .00 21.15 72.72 49.15 0 .00 24.93 81.07 59.95 0 .00 20.76 16 79.38 62.17 0.13 7.882 58.60 40.41 0 .00 23.66 70.21 49.10 0 .00 22.75 8 0.62 60.35 0 .00 25.77 17 76.24 56.05 0 .0 13.66 59.47 37.00 0 .00 22.07 69.28 53.94 0 .00 17.21 78.51 60.51 0 .00 13.98 18 70.14 48.79 0 .00 17.03 60.80 35.92 0 .00 24.27 66.38 46.33 0 .00 25.93 73.11 63.10 0.34 5.849 19 71.69 46.44 0 .00 18.31 63.53 38.52 0 .00 15.58 72.93 45.23 0 .00 24.48 81.93 62.31 0.49 23.23 20 75.47 45.01 0 .00 15.71 71.35 48.63 0 .00 15.68 77.34 47.30 0 .00 27.82 82.35 61.36 0.01 22.74 21 81.95 57.20 0 .00 12.34 77.59 48.61 0 .00 17.56 72.57 56.05 1.04 3.352 81.09 71.51 0 .00 22.67 22 77.95 6 3.97 0.03 8.196 79.45 59.76 0 .00 11.99 70.30 55.33 0.01 21.14 84.36 55.02 0 .00 28.79 23 78.62 56.91 0 .00 12.66 79.79 59.95 0 .00 11.90 70.09 50.23 0 .00 28.47 85.77 56.07 0 .00 28.33 24 83.40 65.55 0 .00 9.426 71.85 52.02 0.04 7.592 78.12 43.94 0 .00 25.70 88 .34 63.16 0 .00 27.60 25 75.58 46.49 0.51 16.20 59.38 35.46 0 .00 25.58 79.59 54.61 0.42 20.45 83.82 68.43 0 .00 14.72 26 69.75 42.88 0 .00 20.43 65.16 31.89 0 .00 26.22 78.21 55.00 0.09 17.71 82.42 62.20 2.02 28.02 27 69.12 39.55 0 .00 21.07 55.76 35.57 0.22 7.778 83.12 50.07 0 .00 27.08 82.20 58.55 0 .00 29.38 28 74.52 44.29 0 .00 20.33 64.87 37.55 0 .00 25.42 77.14 63.84 0.43 6.184 77.50 55.54 0 .00 27.34 29 77.05 50.70 0 .00 13.47 70.79 54.10 1.32 19.03 83.82 52.72 0 .00 29.53 30 77.47 57.70 0.01 8.271 72.27 47.88 0 .00 28.93 78.01 73.02 0.01 17.83 31 62.11 51.15 0 .00 8.490 76.33 45.05 0.02 28.42 Avg 67.14 43.05 0.065 12.29 66.05 45.40 0.089 15.36 72.24 47.99 0.19 19.87 82.36 59.82 0.096 23.95 Max 83.40 65.55 0.99 21.07 79.79 63.72 1.03 26.22 83.12 63.84 2.46 28.93 88.34 71.51 2.02 29.53 Min 45.99 24.57 0 .00 2.173 54.03 31.89 0 .00 2.462 57.22 32.65 0 .00 1.439 73.11 49.6 0 .00 5.849 Total 2.02 380.9 2.48 430.1 5.94 616.0 2.88 718.6

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4 Table 2. Continued. May June July August Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/ Day o F o F inches m 2 o F o F inches m 2 o F o F inches m 2 o F o F inches m 2 1 91 .15 70.50 0 .00 21.97 89.04 69.10 0.01 24.02 91.49 73.49 0.81 15.88 95.43 73.60 3.20 22.94 2 91.40 72.97 0 .00 26.50 90.93 71.11 0.27 25.30 84.45 73.42 0 .00 18.20 96.17 74.32 0.02 25.83 3 90.07 72.93 0.00 27.09 86.00 71.17 0.25 17.59 86.18 73.27 0.42 11.93 94.55 74.80 1.46 24.44 4 86.90 72.14 0.00 27.64 89.47 72.28 0 .00 24.22 83.55 73.02 0.50 8.027 91.94 75.16 0.02 18.78 5 87.22 72.25 0 .00 20.87 91.83 73.72 0.05 23.52 82.62 72.63 0.24 8.637 92.84 73.60 0.88 22.56 6 88.21 68.94 0.00 26.95 90.82 74.66 0 .00 20.99 88.79 71.96 0.05 14.87 93.09 74.64 1.17 25.20 7 91.56 68.43 1.06 24.61 90.86 75.99 0.07 24.16 91.17 72.77 0.01 25.50 91.17 76.66 0 .00 18.41 8 87.31 68.72 0.01 26.57 90.77 73.72 0 .00 24.96 91.56 71.17 0 .00 28.96 87.66 77.14 1.10 5.058 9 88.12 68.8 1 0.00 24.37 88.68 69.48 0.01 26.53 94.50 70.18 0 .00 28.65 90.19 74.71 0.02 18.94 10 84.29 66.11 0.00 26.69 90.12 68.04 0 .00 29.38 93.29 73.58 0 .00 27.48 87.13 75.00 0.53 14.36 11 86.23 65.23 0 .00 23.51 94.59 71.02 0 .00 29.89 90.16 71.29 0 .00 20.77 88.41 74.97 0.17 16.56 12 85.01 64.83 0 .00 27.11 93.02 71.71 0 .00 27.25 89.53 75.43 0.07 16.09 92.79 74.95 0 .00 23.78 13 85.12 65.21 0 .00 27.02 92.25 72.99 0 .00 20.87 93.74 74.10 0 .00 24.61 93.79 76.28 0 .00 25.57 14 86.14 66.09 0 .00 25.58 91.58 72.66 0.04 18 .69 94.68 75.92 0.31 19.32 94.80 75.87 0 .00 25.00 15 87.08 67.33 0 .00 25.54 96.33 73.96 0.04 21.26 92.61 72.79 0.01 15.36 94.35 77.02 0 .00 23.40 16 85.39 67.82 0 .00 19.35 95.70 74.39 0 .00 24.60 91.26 72.68 0 .00 25.16 93.74 76.42 0 .00 16.15 17 83.30 68.4 9 3.06 18.66 92.82 72.64 0.04 14.98 92.86 75.02 0 .00 27.49 95.05 74.97 0 .00 25.95 18 87.04 68.70 0 .00 24.10 92.03 71.11 1.24 16.37 93.24 72.81 0 .00 25.95 94.23 75.47 0 .00 25.25 19 83.66 68.11 0 .00 16.63 92.79 69.98 0.03 27.88 93.96 76.55 0.01 25.07 95.41 75.63 0 .00 23.98 20 89.42 67.06 0 .00 28.42 90.45 71.89 0.26 23.40 94.44 75.16 0 .00 23.94 95.92 74.43 0 .00 22.17 21 88.74 70.38 0 .00 25.97 92.55 71.67 0.60 21.13 94.26 75.04 0 .00 27.07 92.95 74.52 0.02 17.64 22 88.02 68.20 0 .00 26.28 92.46 72.66 0 .00 24 .31 93.81 73.67 0 .00 25.90 91.02 76.23 0.31 19.53 23 89.40 67.66 0 .00 29.76 93.04 73.90 0 .00 27.65 86.25 76.68 1.13 7.318 83.62 75.61 0.62 10.41 24 89.47 66.56 0 .00 27.34 92.66 73.71 0.02 28.30 93.22 76.55 0.70 18.69 87.37 73.90 0.36 5.56 25 27.35 69.08 0.22 23.39 94.57 73.76 0 .00 26.81 92.98 75.61 0.21 23.38 89.08 73.72 0.52 7.47 26 87.01 66.07 0 .00 29.31 94.41 74.97 0.02 23.46 92.95 74.26 0 .00 24.71 91.09 73.44 0 .00 18.49 27 86.31 66.38 0 .00 4.49 94.64 73.67 0.15 23.49 95.72 76.32 0 .00 25.31 91.27 72 .86 1.54 19.26 28 87.91 67.55 0.49 26.09 93.47 74.05 0.30 22.92 97.14 74.21 1.27 25.98 92.19 72.73 0.01 19.05 29 86.43 68.14 0 .00 24.27 92.34 75.06 0.01 23.87 94.19 73.72 0 .00 23.62 90.77 76.23 0 .00 20.96 30 90.30 69.91 0.36 23.98 90.59 73.51 1.24 12.71 94.23 74.70 0 .00 26.09 90.46 74.34 0 .00 18.63 31 91.08 69.37 1.08 28.02 95.18 76.19 0 .00 25.21 91.36 73.85 0 .00 23.07 Avg 87.63 68.39 0.203 25.10 92.03 72.62 0.156 23.35 91.74 74.01 0.185 21.46 91.9 74.94 0.39 19.50 Max 91.56 72.97 3.060 29.76 96.3 3 75.99 1.24 29.89 97.14 76.68 1.27 28.96 96.17 77.14 3.20 25.95 Min 83.30 64.83 0 .00 16.63 86.00 68.04 0 .00 12.71 82.62 70.18 0 .00 7.317 83.62 72.73 0 .00 5.06 Total 6.28 778.1 4.65 700.5 5.74 665.2 11.95 604.4

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5 Table 2. Continued. S eptember October November December Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/ Day o F o F inches m 2 o F o F inches m 2 o F o F inches m 2 o F o F inches m 2 1 91.44 70.38 0 .00 25.21 88.11 63.61 0 .00 19.35 87.48 61.66 0 .00 12.84 68.99 45. 01 0.01 14.34 2 91.44 69.31 0 .00 20.88 88.27 65.97 0 .00 21.49 77.65 70.56 0.14 4.600 65.07 38.93 0 .00 18.57 3 92.17 68.95 0 .00 24.66 85.84 64.00 0 .00 22.47 87.04 64.72 0.38 15.48 67.80 35.14 0 .00 18.66 4 90.73 72.48 0 .00 22.91 83.26 59.04 0 .00 23.62 74. 82 65.70 1.65 6.085 71.87 33.98 0 .00 18.04 5 90.16 72.48 0 .00 15.74 84.94 57.56 0 .00 22.38 66.96 46.33 0.01 19.07 74.98 49.69 0.01 13.65 6 91.51 72.88 0.65 16.67 82.08 59.70 0 .00 23.51 64.60 44.14 0 .00 21.56 54.63 33.70 0 .00 18.48 7 91.17 73.45 0.21 19. 43 82.27 54.39 0 .00 23.74 70.05 43.53 0 .00 20.54 55.17 28.51 0 .00 18.88 8 89.98 74.07 0.53 18.28 85.46 55.31 0 .00 23.91 74.44 46.24 0 .00 20.17 60.78 29.89 0.03 17.99 9 93.09 74.28 0 .00 22.63 86.95 56.57 0 .00 22.77 79.16 43.86 0 .00 20.07 62.80 42.66 0.12 13.47 10 94.05 74.88 0.06 21.55 87.33 58.39 0 .00 19.79 82.17 45.32 0 .00 34.10 71.01 37.86 0 .00 17.68 11 94.08 74.48 0.05 22.76 87.13 58.75 0 .00 22.75 81.12 50.23 0 .00 18.43 66.38 43.14 0 .00 11.60 12 94.86 75.22 0.04 20.34 88.05 62.82 0 .00 28.24 80.24 57 .79 0 .00 18.09 74.35 41.27 0.02 9.756 13 92.30 74.95 0 .00 21.47 87.37 65.17 0 .00 20.23 78.44 53.10 0 .00 18.45 54.30 36.33 0 .00 12.12 14 91.09 72.00 0 .00 21.25 86.25 62.96 0 .00 14.40 78.53 52.21 0 .00 18.23 51.82 27.57 0 .00 18.97 15 91.65 69.29 0 .00 23.30 83.48 52.83 0 .00 22.84 81.34 51.44 0 .00 18.35 59.14 27.13 0 .00 18.36 16 91.62 71.55 0 .00 21.23 81.18 50.94 0 .00 23.24 82.54 58.15 0 .00 15.61 70.70 30.45 0 .00 17.85 17 90.55 72.19 0 .00 22.15 83.97 53.40 0 .00 28.74 83.75 65.43 0 .00 10.84 78.21 51.37 0 .00 17.51 18 91.29 70.11 0 .00 24.19 83.21 55.44 0 .00 22.42 80.85 52.65 0 .00 12.66 69.04 47.14 0.63 4.968 19 89.67 69.76 0.02 18.31 83.73 60.42 0 .00 12.53 79.05 48.49 0 .00 17.06 62.65 50.43 0.01 3.46 8 20 91.27 68.77 0 .00 23.48 85.06 62.38 0 .00 14.00 78.19 55 .09 0 .00 13.10 64.94 38.69 0 .00 17.79 21 90.07 69.24 0 .00 20.12 85.57 57.20 0 .00 19.82 81.23 57.79 0 .00 14.26 73.22 38.18 0 .00 16.95 22 90.36 71.31 0.01 17.55 85.86 59.56 0 .00 18.82 83.66 60.53 0.02 14.24 75.02 42.28 0 .00 15.23 23 91.67 73.35 0.66 18.44 87.31 62.13 0 .00 20.54 83.50 58.37 0 .00 16.96 69.96 44.73 0 .00 17.27 24 90.72 74.26 0 .00 17.29 89.26 67.03 0 .00 20.01 82.72 53.94 0 .00 17.17 70.43 39.19 0 .00 17.67 25 89.92 74.17 0 .00 16.38 90.46 69.71 0 .00 18.11 84.72 57.38 0 .00 15.33 73.31 43.31 0 .00 15.95 26 91.63 71.37 0.28 19.51 91.96 69.98 0 .00 19.24 81.61 65.66 0.04 8.455 65.19 41.07 0.01 13.22 27 91.78 70.95 0.01 21.33 91.24 70.16 0 .00 16.73 74.12 62.40 0.53 5.009 52.43 29.41 0 .00 18.63 28 85.98 73.04 1.08 5.955 92.16 67.24 0 .00 18.81 79.61 54 .28 0 .00 13.39 58.87 25.64 0 .00 18.88 29 86.67 71.76 0 .00 17.41 84.43 63.50 0 .00 16.77 84.54 64.35 0 .00 13.58 68.41 26.81 0 .00 17.82 30 87.55 65.01 0 .00 20.04 86.58 60.48 0 .00 19.45 85.06 65.61 0 .00 13.83 72.25 40.00 0 .00 7.218 31 87.78 57.49 0 .00 1 9.83 79.18 57.61 0 .00 13.43 Avg 91.02 71.86 0.12 20.01 86.44 60.78 0 .00 20.66 79.64 55.90 0.923 15.59 66.55 38.62 0.027 15.30 Max 94.86 75.22 1.08 25.21 92.16 70.16 0 .00 28.74 87.48 70.56 1.65 34.10 79.18 57.61 0.63 18.97 Min 85.98 65.01 0 .00 5.95 8 2.08 50.94 0 .00 15.53 64.60 43.53 0 .00 4.600 51.82 25.64 0 .00 3.468 Total 3.60 600.4 0 .00 640.5 2.77 467.6 0.84 474.4

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6 Rainfall (inches) 0 2 4 6 8 10 12 14 Month January February March April May June July August September October November December 2010 69 yr average Figure 1. Monthly rainfall in 20 10 compared with the 69 year average. Inches 0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 14Month January February March April May June July August September October November December Rain totaled 49.15" Evapo-transpiration totaled 43.33" Figure 2. Monthly rainfall compared with evapotranspiration during 2010. Cumulative rainfall = 49.15 and cumulative evapotranspiration = 43.33

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7 Solar Radiation: Daily solar radiation is shown in Table 2, and 2010 total mo nthly solar radiation can be seen in Figure 3. For interpretation of solar radiation as it pertains to plant growth, 1 MJ results in about 14.3 lb/A of plant dry matter if soil water, temperature, and fertility are not limiting and vegetative cover is com plete. Theoretically, enough solar radiation was received in April 20 10 ( 718.6 MJ) to produce 10, 276 lb/A of plant dry matter. Total solar radiation for 2010 was 7,077 MJ. Solar radiation (MJ) 0 200 400 600 800 1000 Month January February March April May June July August September October November December 2010 Total = 7077 Figure 3. Total monthly solar radiation for 2010. Cumulative solar radiation in 2010 = 7,077 MJ (MJ = Joules x 1,000,000) Temperature D aily low shelter temperatures at or below 32 oF were observed on eight een days (Table 2). The extreme low temperature for 20 10 occurred on 1 2 January when shelter temperature reached 24.6 oF. Scattered frost begins when air temperature drops to 35 oF. Air temperatures at or below 35 F were observed on 25 days in 2010 resulting in widespread or scattered frost across the landscape (data not shown). M ean low temperatures were lower than the 68 year means in January, February, March, October, November, and December in 2010 (Table 3). Overall, mean low temperature for 2009 was 15.1 oF lower than the 6 7 year mean.

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8 Table 3. Summary of minimum temperature* for 20 10 by month, Range Cattle REC. Shelter Ground level 1944 10 20 10 1944 10 20 10 20 10 Month Avg. low Avg. low Extrem e low Year Extreme low Avg. low Extreme low --------------F ------------------------------------F ---------January 49. 2 43.1 18 1981 25 56 46 February 50. 4 45.4 24 2009 32 57 52 March 54. 3 48.0 26 1980 33 60 52 April 5 7.9 59.8 34 1971 50 69 62 May 63. 3 68.4 43 1945 65 77 74 June 70.0 72.6 52 1984 6 8 81 78 July 71.2 74.0 62 several 70 81 78 August 71. 9 74.9 61 1977 7 3 82 80 September 71.1 71.9 51 1962 65 81 78 October 64. 7 60.8 38 2008 51 75 71 November 56.8 55.9 25 1970 4 4 67 62 December 51. 1 39.3 20 1962 26 5 6 50 Average 61.0 45.8 7 0 65 *oC = (oF 32) x 0.555 Air temperature is measured using a thermometer in an instrument shelter designed to protect meteorological equipment from exposure to direct sunlight, precipitation, and condensations, while allowing for adequate ventilation so that the instruments measure environmental parameters accurately. Ground level temperature is measured with a soil probe, which measures the temperature 4 inches below the soil surface. Freeze hazard The fall and spring freeze hazards for the Range Cattle REC are shown in Figure 4. The spring freeze hazard estimates the likelihood of temperatures reaching below the critical temperature after a selected date, while the fall freeze hazard estimates the likelihood of experiencing the first attainment of a critical temperature before a selected date. Based on records from 19 60 to 20 10, these data will not predict what will occur in a given year, but what can be expected over a period of years. In an example us ing the spring freeze hazard, one should expect approximately a 50% chance of survival of a frost susceptible crop (assuming 32 oF) planted before the 1st of February (Figure 4B ). A grower has a significant likelihood of experiencing five crop frosts over ten years by planting before the 1st of February.

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Acknowledgements: The author s thank Toni Wood and Joseph Noel for data preparation. 9 Figure 4. Spring and fall freeze hazard showing temperature probabilities after the spring date and before the fall date. Trend lines for temperature probabilities <28 oF (A), <32 oF (B), <35 oF (C), and <45 oF (D). Graphs were constructed using minimum temperature data from 1960 2010 using FRISKNH as developed by R. Snyder and J. Paulo de MeloAbreu and can be accessed at http://biomet.ucdavis.edu/frost protection.html A B C D


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Title: Climatological report
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Language: English
Creator: Kalmbacher, R. S.
Publisher: University of Florida Range Cattle Station
Place of Publication: Ona, Fla.
Publication Date: 2010
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General Note: Range Cattle Research and Education Center research report RC-1995-1
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Range Cattle Research and Education Center March 2011

Research Report RC-2011-1



CLIMATOLOGICAL REPORT 2010
Range Cattle Research and Education Center

Brent Sellers and Reyna Speckmann


Weather conditions strongly influence agricultural operations from planting
through harvesting. Knowledge of annual rainfall and temperature cycles, along with
their extremes, help producers determine optimum times to prepare and plant seedbeds,
fertilize pastures, apply herbicides, control water, and supplement cattle on pasture or
range. Weather conditions influence seed germination, forage growth, palatability, and
nutritive value.

This research report presents a summary of rainfall, air temperature, evapo-
transpiration, and solar radiation for 2010 obtained at the Range Cattle Research and
Education Center (REC), Ona, Florida, and is compared to a 69-year summary of
rainfall data and a 68-year summary of temperature data collected from this location.
The center is located 810 56.406' W and 270 23.733' N in south central Florida
approximately 45 miles (72 km) east of the Gulf of Mexico and 100 miles (160 km) west
of the Atlantic Ocean.

Weather observations were collected with a Weather Watch 2000 (Campbell
Scientific, Inc) from 1997 until 2005. Beginning in 2006, observations were collected
using the Florida Automated Weather Network (FAWN). Accuracy of rainfall as
measured by the Weather Watch 2000 or FAWN and was verified by comparing with
rainfall measured using US Weather Service standard gauge. Measurements reported
prior to 2006 were recorded at 0900 h; thus, data on a given day represented the
previous 24-hour period. Beginning in 2006, measurements were recorded for an entire
24-h period beginning at midnight.

Rainfall

Annual rainfall for 2010 totaled 49.15 inches (Table 1), which was 4.41 inches
(8.2%) less than the 69-year average of 53.56 inches (Table 1). The lowest annual total
was observed in 2000 when 32.02 inches were measured, and the greatest annual
rainfall total on record was in 1959 when 78.82 inches were recorded.

Characterized by a particularly wet spring, 2010 monthly rainfall totals exceeded
the 69-year average for March, April, May, August, and November (Figure 1; Table 1).
Rainfall deficits exceeding two inches were recorded in June, July, September, and






2


October. Above normal spring rainfall provided some growth of forages for hay,
resulting in a fairly good hay crop.

Daily rainfall equaled or exceeded 1 inch on 20 separate occasions in 2010. Four
of these rain events exceeded 2 inches (Table 2). The single greatest daily rain event
was 1 August when 3.20 inches were recorded.



Table 1. Summary of rainfall by months. Range Cattle REC, 2010.

1942 to 2010 2010
Maximum / Minimum / 69-year Difference from
Month month month average Total 69-year average
-----------------------------------inches----------------------------------------
January 8.45 0.03 2.12 2.02 -0.10
February 9.59 0.02 2.58 2.48 -0.10
March 12.34 0.13 3.12 5.94 2.82
April 11.91 0.00 2.48 2.88 0.40
May 10.58 0.00 3.80 6.28 2.48
June 18.99 2.79 8.62 4.65 -3.97
July 19.74 1.87 8.32 5.74 -2.58
August 16.10 3.13 8.39 11.95 3.56
September 20.11 1.14 7.23 3.60 -3.63
October 11.23 0.00 2.97 0.00 -2.97
November 11.22 0.07 1.91 2.77 0.86
December 8.61 0.16 2.02 0.84 -1.18
Year total 53.56 49.15 -4.41
*Inches x 2.54 = cm.
t Since rainfall records began in July 1942, means for January to June are 68-year
means.


Evapo-transpi ration

Evapo-transpiration is the total amount of water transferred from the earth to the
atmosphere. Evapo-transpiration exceeded rainfall in April, June, September, October,
and December during 2010 (Figure 2). Evapo-transpiration generally exceeds rainfall in
January to May and October to December, which are months with limited rainfall.
Rainfall exceeded evapo-transpiration by 5.82 inches for the entire year.










Table 2. Daily maximum and minimum temperature, precipitation, and solar radiation for 2010,
Range Cattle REC.


January February March April
Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/
Day OF OF inches m2 OF OF inches m2 OF OF inches m2 OF OF inches m2
1 66.4 47.25 0.99 2.742 64.98 51.57 0.05 2.957 72.48 36.41 0.00 25.81 82.38 49.60 0.00 27.80
2 59.2 38.64 0.00 11.45 69.73 54.18 0.06 3.552 73.31 43.85 0.12 11.79 83.05 54.32 0.00 28.34
3 45.99 36.58 0.00 5.402 65.28 52.23 0.00 13.79 57.22 39.19 0.00 16.09 85.21 54.07 0.00 25.21
4 54.81 31.60 0.00 11.10 77.47 50.13 0.00 16.86 58.15 35.29 0.00 26.70 54.25 55.96 0.00 28.19
5 49.37 29.46 0.00 10.58 78.64 61.21 1.03 5.418 63.63 32.65 0.00 26.71 83.61 56.77 0.00 28.58
6 52.27 28.12 0.00 11.14 67.53 55.04 0.00 15.43 67.35 34.80 0.00 27.37 82.89 56.64 0.00 28.38
7 62.11 26.79 0.00 11.44 59.14 41.03 0.00 16.72 71.58 33.72 0.00 27.75 84.42 54.52 0.00 27.05
8 68.9 35.36 0.00 6.755 64.83 37.09 0.00 16.56 74.23 38.38 0.00 2.540 83.75 61.12 0.00 20.06
9 46.67 30.27 0.31 2.173 72.79 49.73 0.06 6.668 74.11 45.63 0.00 1.439 78.64 67.98 0.01 16.69
10 46.31 28.51 0.00 10.59 59.02 42.17 0.00 23.04 80.28 49.86 0.00 20.57 82.35 58.93 0.00 25.83
11 54.07 25.15 0.00 11.36 59.86 36.98 0.00 19.79 80.94 63.36 0.03 7.680 80.87 63.23 0.00 15.36
12 62.6 24.57 0.04 11.46 59.65 47.07 1.02 2.462 66.58 61.57 2.46 2.091 81.95 61.27 0.00 24.53
13 63.27 29.84 0.00 18.54 54.03 63.72 0.00 14.27 71.08 54.09 0.00 26.34 84.16 60.96 0.00 26.89
14 71.82 38.56 0.00 17.59 57.16 33.58 0.00 16.11 71.10 51.87 0.00 23.58 81.54 60.46 0.00 29.16
15 77 49.10 0.00 14.56 71.64 34.28 0.00 21.15 72.72 49.15 0.00 24.93 81.07 59.95 0.00 20.76
16 79.38 62.17 0.13 7.882 58.60 40.41 0.00 23.66 70.21 49.10 0.00 22.75 80.62 60.35 0.00 25.77
17 76.24 56.05 0.0 13.66 59.47 37.00 0.00 22.07 69.28 53.94 0.00 17.21 78.51 60.51 0.00 13.98
18 70.14 48.79 0.00 17.03 60.80 35.92 0.00 24.27 66.38 46.33 0.00 25.93 73.11 63.10 0.34 5.849
19 71.69 46.44 0.00 18.31 63.53 38.52 0.00 15.58 72.93 45.23 0.00 24.48 81.93 62.31 0.49 23.23
20 75.47 45.01 0.00 15.71 71.35 48.63 0.00 15.68 77.34 47.30 0.00 27.82 82.35 61.36 0.01 22.74
21 81.95 57.20 0.00 12.34 77.59 48.61 0.00 17.56 72.57 56.05 1.04 3.352 81.09 71.51 0.00 22.67
22 77.95 63.97 0.03 8.196 79.45 59.76 0.00 11.99 70.30 55.33 0.01 21.14 84.36 55.02 0.00 28.79
23 78.62 56.91 0.00 12.66 79.79 59.95 0.00 11.90 70.09 50.23 0.00 28.47 85.77 56.07 0.00 28.33
24 83.40 65.55 0.00 9.426 71.85 52.02 0.04 7.592 78.12 43.94 0.00 25.70 88.34 63.16 0.00 27.60
25 75.58 46.49 0.51 16.20 59.38 35.46 0.00 25.58 79.59 54.61 0.42 20.45 83.82 68.43 0.00 14.72
26 69.75 42.88 0.00 20.43 65.16 31.89 0.00 26.22 78.21 55.00 0.09 17.71 82.42 62.20 2.02 28.02
27 69.12 39.55 0.00 21.07 55.76 35.57 0.22 7.778 83.12 50.07 0.00 27.08 82.20 58.55 0.00 29.38
28 74.52 44.29 0.00 20.33 64.87 37.55 0.00 25.42 77.14 63.84 0.43 6.184 77.50 55.54 0.00 27.34
29 77.05 50.70 0.00 13.47 70.79 54.10 1.32 19.03 83.82 52.72 0.00 29.53
30 77.47 57.70 0.01 8.271 72.27 47.88 0.00 28.93 78.01 73.02 0.01 17.83
31 62.11 51.15 0.00 8.490 76.33 45.05 0.02 28.42
Avg 67.14 43.05 0.065 12.29 66.05 45.40 0.089 15.36 72.24 47.99 0.19 19.87 82.36 59.82 0.096 23.95
Max 83.40 65.55 0.99 21.07 79.79 63.72 1.03 26.22 83.12 63.84 2.46 28.93 88.34 71.51 2.02 29.53
Min 45.99 24.57 0.00 2.173 54.03 31.89 0.00 2.462 57.22 32.65 0.00 1.439 73.11 49.6 0.00 5.849
Total 2.02 380.9 2.48 430.1 5.94 616.0 2.88 718.6














July


August


Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/
Day F OF inches m2 OF OF inches m2 OF OF inches m2 OF OF inches m2


91.15 70.50
91.40 72.97
90.07 72.93
86.90 72.14
87.22 72.25
88.21 68.94
91.56 68.43
87.31 68.72
88.12 68.81
84.29 66.11
86.23 65.23
85.01 64.83
85.12 65.21
86.14 66.09
87.08 67.33
85.39 67.82
83.30 68.49
87.04 68.70
83.66 68.11
89.42 67.06
88.74 70.38
88.02 68.20
89.40 67.66
89.47 66.56
27.35 69.08
87.01 66.07
86.31 66.38
87.91 67.55
86.43 68.14
90.30 69.91
91.08 69.37


0.00
0.00
0.00
0.00
0.00
0.00
1.06
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
3.06
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.22
0.00
0.00
0.49
0.00
0.36
1.08


21.97
26.50
27.09
27.64
20.87
26.95
24.61
26.57
24.37
26.69
23.51
27.11
27.02
25.58
25.54
19.35
18.66
24.10
16.63
28.42
25.97
26.28
29.76
27.34
23.39
29.31
4.49
26.09
24.27
23.98
28.02


89.04 69.10
90.93 71.11
86.00 71.17
89.47 72.28
91.83 73.72
90.82 74.66
90.86 75.99
90.77 73.72
88.68 69.48
90.12 68.04
94.59 71.02
93.02 71.71
92.25 72.99
91.58 72.66
96.33 73.96
95.70 74.39
92.82 72.64
92.03 71.11
92.79 69.98
90.45 71.89
92.55 71.67
92.46 72.66
93.04 73.90
92.66 73.71
94.57 73.76
94.41 74.97
94.64 73.67
93.47 74.05
92.34 75.06
90.59 73.51


0.01
0.27
0.25
0.00
0.05
0.00
0.07
0.00
0.01
0.00
0.00
0.00
0.00
0.04
0.04
0.00
0.04
1.24
0.03
0.26
0.60
0.00
0.00
0.02
0.00
0.02
0.15
0.30
0.01
1.24


24.02
25.30
17.59
24.22
23.52
20.99
24.16
24.96
26.53
29.38
29.89
27.25
20.87
18.69
21.26
24.60
14.98
16.37
27.88
23.40
21.13
24.31
27.65
28.30
26.81
23.46
23.49
22.92
23.87
12.71


Table 2. Continued.


May


June


91.49 73.49
84.45 73.42
86.18 73.27
83.55 73.02
82.62 72.63
88.79 71.96
91.17 72.77
91.56 71.17
94.50 70.18
93.29 73.58
90.16 71.29
89.53 75.43
93.74 74.10
94.68 75.92
92.61 72.79
91.26 72.68
92.86 75.02
93.24 72.81
93.96 76.55
94.44 75.16
94.26 75.04
93.81 73.67
86.25 76.68
93.22 76.55
92.98 75.61
92.95 74.26
95.72 76.32
97.14 74.21
94.19 73.72
94.23 74.70
95.18 76.19


0.81
0.00
0.42
0.50
0.24
0.05
0.01
0.00
0.00
0.00
0.00
0.07
0.00
0.31
0.01
0.00
0.00
0.00
0.01
0.00
0.00
0.00
1.13
0.70
0.21
0.00
0.00
1.27
0.00
0.00
0.00


15.88
18.20
11.93
8.027
8.637
14.87
25.50
28.96
28.65
27.48
20.77
16.09
24.61
19.32
15.36
25.16
27.49
25.95
25.07
23.94
27.07
25.90
7.318
18.69
23.38
24.71
25.31
25.98
23.62
26.09
25.21


95.43 73.60
96.17 74.32
94.55 74.80
91.94 75.16
92.84 73.60
93.09 74.64
91.17 76.66
87.66 77.14
90.19 74.71
87.13 75.00
88.41 74.97
92.79 74.95
93.79 76.28
94.80 75.87
94.35 77.02
93.74 76.42
95.05 74.97
94.23 75.47
95.41 75.63
95.92 74.43
92.95 74.52
91.02 76.23
83.62 75.61
87.37 73.90
89.08 73.72
91.09 73.44
91.27 72.86
92.19 72.73
90.77 76.23
90.46 74.34
91.36 73.85


3.20
0.02
1.46
0.02
0.88
1.17
0.00
1.10
0.02
0.53
0.17
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.02
0.31
0.62
0.36
0.52
0.00
1.54
0.01
0.00
0.00
0.00


22.94
25.83
24.44
18.78
22.56
25.20
18.41
5.058
18.94
14.36
16.56
23.78
25.57
25.00
23.40
16.15
25.95
25.25
23.98
22.17
17.64
19.53
10.41
5.56
7.47
18.49
19.26
19.05
20.96
18.63
23.07


Avq 87.63 68.39 0.203 25.10 92.03 72.62 0.156 23.35 91.74 74.01 0.185 21.46 91.9 74.94 0.39 19.50
Max 91.56 72.97 3.060 29.76 96.33 75.99 1.24 29.89 97.14 76.68 1.27 28.96 96.17 77.14 3.20 25.95
Min 83.30 64.83 0.00 16.63 86.00 68.04 0.00 12.71 82.62 70.18 0.00 7.317 83.62 72.73 0.00 5.06
Total 6.28 778.1 4.65 700.5 5.74 665.2 11.95 604.4










Table 2. Continued.

September October November December
Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/ Max Min Rain MJ/
Day OF OF inches m2 OF OF inches m2 OF OF inches m2 OF OF inches m2
1 91.44 70.38 0.00 25.21 88.11 63.61 0.00 19.35 87.48 61.66 0.00 12.84 68.99 45.01 0.01 14.34
2 91.44 69.31 0.00 20.88 88.27 65.97 0.00 21.49 77.65 70.56 0.14 4.600 65.07 38.93 0.00 18.57
3 92.17 68.95 0.00 24.66 85.84 64.00 0.00 22.47 87.04 64.72 0.38 15.48 67.80 35.14 0.00 18.66
4 90.73 72.48 0.00 22.91 83.26 59.04 0.00 23.62 74.82 65.70 1.65 6.085 71.87 33.98 0.00 18.04
5 90.16 72.48 0.00 15.74 84.94 57.56 0.00 22.38 66.96 46.33 0.01 19.07 74.98 49.69 0.01 13.65
6 91.51 72.88 0.65 16.67 82.08 59.70 0.00 23.51 64.60 44.14 0.00 21.56 54.63 33.70 0.00 18.48
7 91.17 73.45 0.21 19.43 82.27 54.39 0.00 23.74 70.05 43.53 0.00 20.54 55.17 28.51 0.00 18.88
8 89.98 74.07 0.53 18.28 85.46 55.31 0.00 23.91 74.44 46.24 0.00 20.17 60.78 29.89 0.03 17.99
9 93.09 74.28 0.00 22.63 86.95 56.57 0.00 22.77 79.16 43.86 0.00 20.07 62.80 42.66 0.12 13.47
10 94.05 74.88 0.06 21.55 87.33 58.39 0.00 19.79 82.17 45.32 0.00 34.10 71.01 37.86 0.00 17.68
11 94.08 74.48 0.05 22.76 87.13 58.75 0.00 22.75 81.12 50.23 0.00 18.43 66.38 43.14 0.00 11.60
12 94.86 75.22 0.04 20.34 88.05 62.82 0.00 28.24 80.24 57.79 0.00 18.09 74.35 41.27 0.02 9.756
13 92.30 74.95 0.00 21.47 87.37 65.17 0.00 20.23 78.44 53.10 0.00 18.45 54.30 36.33 0.00 12.12
14 91.09 72.00 0.00 21.25 86.25 62.96 0.00 14.40 78.53 52.21 0.00 18.23 51.82 27.57 0.00 18.97
15 91.65 69.29 0.00 23.30 83.48 52.83 0.00 22.84 81.34 51.44 0.00 18.35 59.14 27.13 0.00 18.36
16 91.62 71.55 0.00 21.23 81.18 50.94 0.00 23.24 82.54 58.15 0.00 15.61 70.70 30.45 0.00 17.85
17 90.55 72.19 0.00 22.15 83.97 53.40 0.00 28.74 83.75 65.43 0.00 10.84 78.21 51.37 0.00 17.51
18 91.29 70.11 0.00 24.19 83.21 55.44 0.00 22.42 80.85 52.65 0.00 12.66 69.04 47.14 0.63 4.968
19 89.67 69.76 0.02 18.31 83.73 60.42 0.00 12.53 79.05 48.49 0.00 17.06 62.65 50.43 0.01 3.468
20 91.27 68.77 0.00 23.48 85.06 62.38 0.00 14.00 78.19 55.09 0.00 13.10 64.94 38.69 0.00 17.79
21 90.07 69.24 0.00 20.12 85.57 57.20 0.00 19.82 81.23 57.79 0.00 14.26 73.22 38.18 0.00 16.95
22 90.36 71.31 0.01 17.55 85.86 59.56 0.00 18.82 83.66 60.53 0.02 14.24 75.02 42.28 0.00 15.23
23 91.67 73.35 0.66 18.44 87.31 62.13 0.00 20.54 83.50 58.37 0.00 16.96 69.96 44.73 0.00 17.27
24 90.72 74.26 0.00 17.29 89.26 67.03 0.00 20.01 82.72 53.94 0.00 17.17 70.43 39.19 0.00 17.67
25 89.92 74.17 0.00 16.38 90.46 69.71 0.00 18.11 84.72 57.38 0.00 15.33 73.31 43.31 0.00 15.95
26 91.63 71.37 0.28 19.51 91.96 69.98 0.00 19.24 81.61 65.66 0.04 8.455 65.19 41.07 0.01 13.22
27 91.78 70.95 0.01 21.33 91.24 70.16 0.00 16.73 74.12 62.40 0.53 5.009 52.43 29.41 0.00 18.63
28 85.98 73.04 1.08 5.955 92.16 67.24 0.00 18.81 79.61 54.28 0.00 13.39 58.87 25.64 0.00 18.88
29 86.67 71.76 0.00 17.41 84.43 63.50 0.00 16.77 84.54 64.35 0.00 13.58 68.41 26.81 0.00 17.82
30 87.55 65.01 0.00 20.04 86.58 60.48 0.00 19.45 85.06 65.61 0.00 13.83 72.25 40.00 0.00 7.218
31 87.78 57.49 0.00 19.83 79.18 57.61 0.00 13.43
Avq 91.02 71.86 0.12 20.01 86.44 60.78 0.00 20.66 79.64 55.90 0.923 15.59 66.55 38.62 0.027 15.30
Max 94.86 75.22 1.08 25.21 92.16 70.16 0.00 28.74 87.48 70.56 1.65 34.10 79.18 57.61 0.63 18.97
Min 85.98 65.01 0.00 5.95 82.08 50.94 0.00 15.53 64.60 43.53 0.00 4.600 51.82 25.64 0.00 3.468
Total 3.60 600.4 0.00 640.5 2.77 467.6 0.84 474.4














December
November
October
September
August
July
June
May
April
March
February -
January -


0 2


4 6 8 10 12 14


Rainfall (inches)


Figure 1. Monthly rainfall in 2010 compared with the 69-year average.


2 4


6 8 10 12

I I Rain totaled 49.15"
I I Evapo-transpiration totaled 43.33"


2 4 6 8 10 12 14

Inches


Figure 2. Monthly rainfall compared with evapo-transpiration during 2010.
rainfall = 49.15" and cumulative evapo-transpiration = 43.33".


Cumulative


I- 2010
[ 69 yr average


i


December
November
October
September
August
July
June
May
April
March
February
January


-











Solar Radiation:

Daily solar radiation is shown in Table 2, and 2010 total monthly solar radiation can be
seen in Figure 3. For interpretation of solar radiation as it pertains to plant growth, 1 MJ
results in about 14.3 Ib/A of plant dry matter if soil water, temperature, and fertility are not
limiting and vegetative cover is complete. Theoretically, enough solar radiation was received
in April 2010 (718.6 MJ) to produce 10,276 Ib/A of plant dry matter. Total solar radiation for
2010 was 7,077 MJ.


December -
November -
October -
September -
August -
July -
June -
May -
April -
March -
February -
January -


200 400 600 800 1000


Solar radiation (MJ)


Figure 3. Total monthly solar radiation for 2010. Cumulative
MJ (MJ = Joules x 1,000,000)


solar radiation in 2010 = 7,077


Temperature

Daily-low shelter temperatures at or below 32 OF were observed on eighteen
days(Table 2). The extreme low temperature for 2010 occurred on 12 January when shelter
temperature reached 24.6 OF. Scattered frost begins when air temperature drops to 35 OF.
Air temperatures at or below 350F were observed on 25 days in 2010, resulting in widespread
or scattered frost across the landscape (data not shown). Mean low temperatures were lower
than the 68-year means in January, February, March, October, November, and December in
2010 (Table 3). Overall, mean low temperature for 2009 was 15.1 OF lower than the 67-year
mean.


I 2010 Total = 7077


I












Table 3. Summary of minimum temperature for 2010 by month, Range Cattle REC.

Shelter Ground level:
1944-10 2010 1944-10 2010 2010
Avg. Avg. Extreme Extreme Avg. Extreme
Month low low low Year low low low
-------OF----------------- ---------- ------------OF----------
January 49.2 43.1 18 1981 25 56 46
February 50.4 45.4 24 2009 32 57 52
March 54.3 48.0 26 1980 33 60 52
April 57.9 59.8 34 1971 50 69 62
May 63.3 68.4 43 1945 65 77 74
June 70.0 72.6 52 1984 68 81 78
July 71.2 74.0 62 several 70 81 78
August 71.9 74.9 61 1977 73 82 80
September 71.1 71.9 51 1962 65 81 78
October 64.7 60.8 38 2008 51 75 71
November 56.8 55.9 25 1970 44 67 62
December 51.1 39.3 20 1962 26 56 50
Average 61.0 45.8 70 65
C = (oF 32) x 0.555
t Air temperature is measured using a thermometer in an instrument shelter designed to
protect meteorological equipment from exposure to direct sunlight, precipitation, and
condensations, while allowing for adequate ventilation so that the instruments measure
environmental parameters accurately.
$ Ground level temperature is measured with a soil probe, which measures the temperature 4
inches below the soil surface.

Freeze hazard

The fall and spring freeze hazards for the Range Cattle REC are shown in Figure 4.
The spring freeze hazard estimates the likelihood of temperatures reaching below the critical
temperature after a selected date, while the fall freeze hazard estimates the likelihood of
experiencing the first attainment of a critical temperature before a selected date. Based on
records from 1960 to 2010, these data will not predict what will occur in a given year, but
what can be expected over a period of years. In an example using the spring freeze hazard,
one should expect approximately a 50% chance of survival of a frost-susceptible crop
(assuming 32 OF) planted before the 1st of February (Figure 4-B). A grower has a significant
likelihood of experiencing five crop frosts over ten years by planting before the 1st of February.














Ion




t
S so


Gol
a

t m
40

20


100



- N' c



40 .. ... . . -


E
G
* S

0
k
Sc -
t
B


0 -
I


100



IB I


Be



4:
a"'





0


100
















0
100

-
a



4o0












20
w


*E


1!311?1! i S 1


Figure 4. Spring and fall freeze hazard showing temperature probabilities after the spring date and before the fall date.
Trend lines for temperature probabilities <28 OF (A), <32 OF (B), <35 OF (C), and <45 OF (D). Graphs were constructed
using minimum temperature data from 1960 2010 using FRISKNH as developed by R. Snyder and J. Paulo de Melo-
Abreu and can be accessed at httD://biomet.ucdavis.edu/frost-Drotection.html


Acknowledgements: The authors thank Toni Wood and Joseph Noel for data preparation.




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