SAINT HELENA, CALIFORNIA

Period of Record General Climate Summary - Growing Degree Days

Station:(047643) SAINT HELENA
From Year=1931 To Year=2006
Growing Degree Days for Selected Base Temperature (F)
Base Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Annual
40 M 212 287 402 513 702 831 966 948 840 671 399 232 7002
40 S 212 498 900 1413 2115 2945 3911 4859 5699 6370 6769 7002 7002
45 M 94 156 251 363 547 681 811 793 690 516 253 108 5262
45 S 94 250 500 864 1411 2092 2903 3696 4386 4902 5154 5262 5262
50 M 27 59 123 221 393 531 656 638 540 362 127 33 3709
50 S 27 86 209 430 823 1354 2009 2648 3187 3549 3676 3709 3709
55 M 4 13 43 106 244 381 501 483 390 215 45 5 2430
55 S 4 18 60 166 410 791 1292 1775 2165 2380 2424 2430 2430
60 M 1 1 9 36 121 235 346 328 243 96 10 0 1427
60 S 1 2 11 48 169 404 749 1078 1320 1417 1427 1427 1427
Corn Growing Degree Days
50 M 114 162 241 323 433 509 588 581 519 424 244 126 4264
50 S 114 276 517 840 1273 1782 2370 2951 3470 3894 4138 4264 4264
M = Monthly Data
S - Running sum of monthly data.
Growing Degree Day units are computed as the difference between the daily average temperature and the base temperature. (Daily Ave. Temp. - Base Temp.) One unit is accumulated for each degree Fahrenheit the average temperature is above the base temperature. Negative numbers are discarded. Example: If the days high temperature was 95 and the low temperature was 51, the base 60 heating degree day units is ((95 + 51) / 2) - 60 = 13. This is done for each day of the month and summed.
Corn Growing Degree Day units have the limitations that the maximum daily temperatures greater than 86 F are set to 86 F and minimums less than 50 F are set to 50 F.
Table updated on Jul 28, 2006
Months with 5 or more missing days are not considered
Years with 1 or more missing months are not considered

Western Regional Climate Center, wrcc@dri.edu