SEATTLE URBAN SITE, WASHINGTON

Period of Record General Climate Summary - Growing Degree Days

Station:(457458) SEATTLE URBAN SITE
From Year=1972 To Year=1998
Growing Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
40 M	110	141	232	344	525	645	793	804	648	423	198	101	4962
40 S	110	250	482	826	1351	1995	2788	3592	4240	4663	4861	4962	4962
45 M	32	48	96	195	370	495	638	649	498	270	85	29	3405
45 S	32	80	176	372	742	1236	1874	2523	3021	3291	3375	3405	3405
50 M	4	8	19	76	217	345	483	494	348	128	22	4	2146
50 S	4	11	31	107	323	668	1151	1645	1993	2121	2142	2146	2146
55 M	0	0	1	19	91	196	328	339	200	36	3	0	1214
55 S	0	1	2	21	112	308	636	975	1175	1212	1214	1214	1214
60 M	0	0	0	2	28	73	175	186	78	4	0	0	548
60 S	0	0	0	2	31	103	278	465	543	548	548	548	548

Corn Growing Degree Days
50 M	17	38	82	144	250	348	480	492	355	172	47	14	2439
50 S	17	55	137	281	531	879	1359	1851	2206	2378	2425	2439	2439

M = Monthly Data
S - Running sum of monthly data.
Growing Degree Day units are computed as the difference between the daily average temperature and the base temperature. (Daily Ave. Temp. - Base Temp.) One unit is accumulated for each degree Fahrenheit the average temperature is above the base temperature. Negative numbers are discarded. Example: If the days high temperature was 95 and the low temperature was 51, the base 60 heating degree day units is ((95 + 51) / 2) - 60 = 13. This is done for each day of the month and summed.
Corn Growing Degree Day units have the limitations that the maximum daily temperatures greater than 86 F are set to 86 F and minimums less than 50 F are set to 50 F.
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