PORTLAND INTL AP, OREGON

Period of Record General Climate Summary - Heating Degree Days

Station:(356751) PORTLAND WSFO
From Year=1941 To Year=2012
Heating Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
65	786	614	563	412	247	103	24	20	88	328	570	752	4506
60	631	473	408	266	123	27	2	1	22	184	420	597	3154
57	538	388	316	185	66	7	0	0	7	112	331	504	2455
55	476	332	255	136	38	2	0	0	3	75	273	443	2034
50	324	197	120	43	5	0	0	0	0	19	143	291	1142

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