Growing Degree Day Averages
Derived from 1971-1993 Data
| Element | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN |
| GDD Base 40 |
0 | 3 | 45 | 240 | 573 | 805 | 975 | 862 | 576 | 268 | 44 | 1 | 4296 |
| GDD Base 45 |
0 | 1 | 19 | 146 | 423 | 657 | 821 | 714 | 432 | 160 | 17 | 0 | 3315 |
| GDD Base 50 |
0 | 0 | 8 | 82 | 286 | 509 | 667 | 567 | 298 | 84 | 5 | 0 | 2448 |
| GDD Base 55 |
0 | 0 | 2 | 42 | 173 | 363 | 514 | 420 | 182 | 36 | 1 | 0 | 1692 |
| GDD Base 60 |
0 | 0 | 0 | 19 | 91 | 228 | 361 | 279 | 95 | 14 | 0 | 0 | 1062 |
| MGDD* Base 50 |
0 | 4 | 38 | 178 | 386 | 529 | 642 | 567 | 374 | 197 | 34 | 1 | 2887 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/19 | 5/01 | 5/05 | 6/01 | 6/22 | 9/23 | 8/28 | 9/02 | 10/04 | 10/07 |
| 30 | 5/13 | 4/21 | 4/27 | 6/01 | 6/22 | 9/27 | 8/28 | 9/13 | 10/07 | 10/10 |
| 28 | 5/06 | 4/16 | 4/24 | 5/19 | 5/25 | 9/30 | 8/28 | 9/15 | 10/10 | 11/04 |
| 24 | 4/19 | 3/30 | 4/03 | 4/30 | 5/06 | 10/07 | 9/07 | 9/25 | 10/28 | 11/04 |
| 20 | 4/09 | 3/23 | 3/26 | 4/21 | 4/22 | 10/19 | 9/27 | 10/02 | 11/07 | 11/12 |
| 16 | 4/03 | 2/22 | 3/13 | 4/11 | 4/17 | 11/05 | 10/10 | 10/22 | 11/20 | 11/25 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 123 | 94 | 97 | 144 | 149 |
| 30 | 140 | 99 | 101 | 153 | 155 |
| 28 | 149 | 100 | 130 | 164 | 173 |
| 24 | 175 | 138 | 153 | 203 | 219 |
| 20 | 192 | 167 | 175 | 212 | 226 |
| 16 | 222 | 190 | 200 | 247 | 257 |