VASHON ISLAND, WASHINGTON

Period of Record General Climate Summary - Heating Degree Days

Station:(458802) VASHON ISLAND
From Year=1891 To Year=1955
Heating Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
65	815	670	639	479	334	189	91	93	202	419	587	745	5263
60	660	529	484	330	188	70	14	17	81	266	438	590	3665
57	567	444	391	243	111	26	2	3	35	180	348	497	2846
55	505	388	330	188	69	10	0	1	16	128	288	435	2360
50	352	248	183	72	11	0	0	0	1	38	149	282	1338

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