SEATTLE NAS, WASHINGTON

Period of Record General Climate Summary - Heating Degree Days

Station:(457468) SEATTLE NAVAL AIR STN
From Year=1929 To Year=1970
Heating Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
65	782	608	609	443	282	140	51	49	140	353	571	702	4730
60	627	467	454	295	146	40	5	4	42	204	421	547	3250
57	534	382	361	209	81	11	1	0	13	125	331	454	2502
55	472	326	300	155	47	3	0	0	5	82	272	392	2055
50	318	190	155	48	6	0	0	0	0	18	138	240	1113

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