Historical Climate Data

Growing Season Summary
Station: 473471 HATFIELD DAM, WI

Growing Degree Day Averages
Derived from 1971-1998 Data

Element JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANN
GDD
Base 40		 0 1 41 222 543 749 921 880 592 281 42 1 4128
GDD
Base 45		 0 0 18 130 393 603 769 725 445 168 17 0 3151
GDD
Base 50		 0 0 7 69 259 458 617 570 307 87 5 0 2289
GDD
Base 55		 0 0 2 33 150 316 465 415 189 37 0 0 1546
GDD
Base 60		 0 0 0 14 77 190 316 267 98 11 0 0 940
MGDD*
Base 50		 0 3 36 178 375 493 607 577 387 196 32 1 2794

*Modified Growing Degree Days: Base 50 Ceiling 86.

Growing Season Summary
Derived from 1971-1998 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 6/01 5/02 5/11 6/11 6/21 9/19 9/01 9/08 10/02 10/06
30 5/22 5/02 5/03 6/10 6/21 9/23 9/03 9/10 10/02 10/06
28 5/13 4/26 5/02 5/29 6/11 10/01 9/03 9/21 10/09 10/16
24 4/25 4/04 4/09 5/10 5/27 10/08 9/20 9/27 10/31 11/02
20 4/18 4/02 4/05 4/29 5/03 10/28 9/23 10/04 11/06 11/12
16 4/09 3/20 3/25 4/23 4/26 11/02 10/02 10/13 11/13 11/15

Length of Growing Season (Days)
Derived from 1971-1998 Averages

Base
Temp
°F		 Median Shortest 10% 90% Longest
32 112 89 95 136 139
30 124 101 104 141 146
28 136 112 117 156 168
24 166 126 139 190 194
20 191 152 170 212 218
16 210 161 176 221 226