SAINT HELENA, CALIFORNIA

Period of Record General Climate Summary - Cooling Degree Days

Station:(047643) SAINT HELENA
From Year=1931 To Year=2006
Cooling Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
55	4	13	43	106	244	381	501	483	390	215	45	5	2430
57	2	6	25	72	190	322	439	421	330	163	26	2	1998
60	1	1	9	36	121	235	346	328	243	96	10	0	1427
65	0	0	1	9	45	111	194	177	115	29	2	0	683
70	0	0	0	1	12	39	72	61	38	6	0	0	230

Cooling 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.
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