SAN FRANCISCO INTL AP, CALIFORNIA

Period of Record General Climate Summary - Growing Degree Days

Station:(047769) SAN FRANCISCO WSO AP
From Year=1948 To Year=2012
Growing Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
40 M	286	341	425	473	573	641	705	730	724	655	455	305	6312
40 S	286	626	1051	1524	2097	2739	3444	4173	4897	5552	6006	6312	6312
45 M	143	201	270	323	418	491	550	575	574	500	305	159	4510
45 S	143	345	615	938	1356	1848	2398	2972	3546	4046	4350	4510	4510
50 M	44	80	125	176	264	341	395	420	424	345	162	53	2827
50 S	44	124	249	425	688	1030	1425	1844	2268	2613	2774	2827	2827
55 M	6	15	33	60	117	192	240	265	274	193	54	8	1455
55 S	6	21	54	114	230	422	662	927	1200	1393	1447	1455	1455
60 M	0	1	5	14	34	68	94	114	129	70	9	0	538
60 S	0	1	6	20	54	122	216	330	458	529	538	538	538

Corn Growing Degree Days
50 M	97	134	180	215	279	341	394	419	419	355	206	107	3145
50 S	97	231	411	626	905	1246	1639	2058	2477	2832	3039	3145	3145

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 Oct 31, 2012
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