SEATTLE TCOMA WSCMO AP, WASHINGTON

Period of Record General Climate Summary - Heating Degree Days

Station:(457473) SEATTLE TCOMA WSCMO AP
From Year=1931 To Year=2006
Heating Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
65	775	627	613	469	306	159	62	57	155	391	601	752	4968
60	620	486	459	321	168	54	8	6	53	240	451	597	3462
57	527	402	366	236	99	18	1	1	20	158	361	504	2691
55	465	345	305	182	62	7	0	0	9	110	302	442	2229
50	312	210	161	68	10	0	0	0	1	31	165	289	1247

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 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