Historical Climate Data

Growing Season Summary
Station: 470045 AFTON, WI

Growing Degree Day Averages
Derived from 1987-2000 Data

 ElementJAN FEB MAR APRMAY JUN JUL AUGSEP OCT NOV DECANN
 GDD
 Base 401   8   72  221580 848 994 932645 304 62  7  4629
 GDD
 Base 450   2   37  123428 698 839 778497 188 27  3  3584
 GDD
 Base 500   0   17  60 288 548 684 624353 106 10  1  2662
 GDD
 Base 550   0   7   27 172 402 530 470224 49  3   0  1861
 GDD
 Base 600   0   2   10 91  264 376 319124 17  0   0  1189
 MGDD*
 Base 502   5   50  140349 548 661 612402 197 38  4  2981

*Modified Growing Degree Days: Base 50 Ceiling 86.

Growing Season Summary
Derived from 1987-2000 Averages

     Date of Last Spring Occurrence Date of First Fall Occurrence
 Base
 Temp
 °F  Median  Early  90%  10%  Late  Median Early 90%  10%   Late
 32  4/29    4/22   4/23 5/18 5/27  10/06  9/21  9/23 10/16 10/22
 30  4/22    3/29   4/06 5/18 5/27  10/08  9/23  9/23 10/19 10/22
 28  4/14    3/27   4/01 4/30 5/06  10/12  9/23  10/0110/25 10/27
 24  4/08    3/24   3/26 4/18 4/19  11/01  10/13 10/1811/16 11/15
 20  3/30    3/17   3/19 4/09 4/10  11/04  10/19 10/2812/11 12/21
 16  3/16    2/21   2/27 4/06 4/09  11/17  10/29 11/0212/11 12/22

Length of Growing Season (Days)
Derived from 1987-2000 Averages

 Base
 Temp
 °F  Median Shortest 10% 90%Longest
 32  153    125      135 173177
 30  161    140      142 190199
 28  178    150      160 204211
 24  204    177      189 223228
 20  218    208      209 255279
 16  244    218      221 280281