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Period of Record General Climate Summary - Growing Degree Days

Station:(217460) SANDY LAKE DAM LIBBY
From Year=1893 To Year=2012
Growing Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
40 M	0	0	10	124	423	684	864	792	499	219	19	0	3635
40 S	0	0	10	135	558	1241	2105	2898	3396	3616	3635	3635	3635
45 M	0	0	3	63	286	534	709	637	357	124	5	0	2717
45 S	0	0	3	66	352	885	1594	2232	2588	2712	2717	2717	2717
50 M	0	0	1	27	170	387	554	483	229	59	1	0	1911
50 S	0	0	1	28	198	584	1138	1621	1850	1910	1911	1911	1911
55 M	0	0	0	10	87	249	400	332	129	22	0	0	1228
55 S	0	0	0	10	97	346	745	1077	1206	1228	1228	1228	1228
60 M	0	0	0	3	36	134	252	195	61	6	0	0	687
60 S	0	0	0	3	39	173	425	620	682	687	687	687	687

Corn Growing Degree Days
50 M	0	0	8	93	261	419	556	500	293	128	12	0	2271
50 S	0	0	9	102	363	782	1338	1838	2131	2259	2271	2271	2271

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 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