LEWISTON WTP, IDAHO

Period of Record General Climate Summary - Growing Degree Days

Station:(105236) LEWISTON WATER PLANT
From Year=1894 To Year=1955
Growing Degree Days for Selected Base Temperature (F)
Base	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Annual
40 M	30	53	171	405	654	808	1113	1067	758	420	109	36	5625
40 S	30	84	255	660	1314	2122	3235	4302	5060	5480	5589	5625	5625
45 M	5	11	71	260	499	658	958	912	608	274	37	6	4300
45 S	5	16	87	347	846	1504	2462	3375	3983	4257	4294	4300	4300
50 M	1	1	20	135	347	508	803	757	460	148	6	0	3186
50 S	1	1	22	157	504	1012	1815	2572	3032	3180	3185	3186	3186
55 M	0	0	3	53	209	359	648	602	316	58	0	0	2249
55 S	0	0	3	56	265	624	1272	1875	2191	2249	2249	2249	2249
60 M	0	0	0	15	101	220	493	448	187	14	0	0	1479
60 S	0	0	0	15	117	336	830	1278	1465	1479	1479	1479	1479

Corn Growing Degree Days
50 M	10	29	110	256	405	498	678	646	471	260	50	10	3424
50 S	10	38	149	405	810	1308	1986	2632	3103	3364	3414	3424	3424

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