Growing Degree Day Averages
Derived from 1971-2000 Data
| Element | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN |
| GDD Base 40 |
1 | 3 | 60 | 267 | 584 | 824 | 995 | 910 | 632 | 315 | 72 | 4 | 4670 |
| GDD Base 45 |
0 | 1 | 27 | 165 | 433 | 675 | 840 | 756 | 484 | 194 | 32 | 1 | 3610 |
| GDD Base 50 |
0 | 0 | 12 | 91 | 292 | 525 | 685 | 601 | 341 | 104 | 11 | 0 | 2666 |
| GDD Base 55 |
0 | 0 | 4 | 47 | 175 | 377 | 530 | 446 | 218 | 46 | 2 | 0 | 1849 |
| GDD Base 60 |
0 | 0 | 1 | 22 | 92 | 236 | 376 | 296 | 120 | 16 | 0 | 0 | 1162 |
| MGDD* Base 50 |
0 | 3 | 42 | 181 | 375 | 537 | 665 | 601 | 395 | 192 | 42 | 2 | 3038 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/10 | 4/19 | 4/28 | 5/26 | 5/30 | 9/27 | 9/12 | 9/19 | 10/09 | 10/17 |
| 30 | 5/06 | 4/09 | 4/20 | 5/12 | 5/17 | 10/05 | 9/12 | 9/23 | 10/16 | 10/19 |
| 28 | 5/01 | 4/08 | 4/09 | 5/09 | 5/10 | 10/07 | 9/22 | 9/24 | 10/20 | 11/01 |
| 24 | 4/17 | 3/29 | 4/05 | 5/03 | 5/07 | 10/21 | 9/22 | 10/04 | 11/06 | 11/08 |
| 20 | 4/08 | 3/23 | 3/26 | 4/19 | 4/22 | 11/01 | 10/02 | 10/11 | 11/10 | 11/20 |
| 16 | 3/26 | 3/06 | 3/15 | 4/09 | 4/11 | 11/11 | 10/20 | 10/26 | 11/24 | 12/04 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 140 | 110 | 120 | 155 | 160 |
| 30 | 153 | 134 | 138 | 170 | 185 |
| 28 | 159 | 137 | 139 | 183 | 185 |
| 24 | 190 | 151 | 161 | 209 | 214 |
| 20 | 208 | 176 | 182 | 223 | 227 |
| 16 | 223 | 194 | 208 | 251 | 259 |