SAN FRANCISCO INTL AP, CALIFORNIA

Period of Record General Climate Summary - Heating Degree Days

Station:(047769) SAN FRANCISCO WSO AP
From Year=1948 To Year=2012
Heating Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
65	490	366	351	280	210	128	89	68	66	138	296	471	2953
60	335	225	200	141	80	27	9	4	5	36	154	316	1533
57	244	145	118	71	26	4	1	0	0	9	84	226	929
55	186	98	73	37	8	0	0	0	0	3	49	169	625
50	69	22	11	3	0	0	0	0	0	0	7	59	170

Heating Degree Day units are computed as the difference between the base temperature and the daily average temperature. (Base Temp. - Daily Ave. Temp.) One unit is accumulated for each degree Fahrenheit the average temperature is below the base temperature. Negative numbers are discarded. Example: If the days high temperature was 65 and the low temperature was 31, the base 50 heating degree day units is 50 - ((65 + 31) / 2) = 2. This is done for each day of the month and summed.
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