SEATTLE BOEING FIELD, WASHINGTON

Period of Record General Climate Summary - Heating Degree Days

Station:(457483) SEATTLE WB AIRPORT
From Year=1948 To Year=1965
Heating Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
65	795	616	622	434	266	123	42	43	143	367	583	711	4745
60	640	475	467	285	133	32	3	3	46	218	433	556	3290
57	547	390	374	199	72	8	1	0	17	140	343	463	2554
55	485	334	312	146	41	3	0	0	8	96	284	401	2110
50	332	199	165	42	5	0	0	0	1	25	150	250	1169

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