PETALUMA AP, CALIFORNIA

Period of Record General Climate Summary - Heating Degree Days

Station:(046826) PETALUMA FIRE STN 3
From Year=1893 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	550	403	374	286	190	76	26	24	41	133	345	532	2979
60	395	263	223	150	71	12	1	2	4	40	202	378	1741
57	304	182	141	83	28	3	0	0	1	14	127	287	1169
55	245	133	96	50	12	1	0	0	0	6	86	229	858
50	113	44	24	8	1	0	0	0	0	1	22	104	316

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