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 | 7 | 66 | 242 | 571 | 834 | 986 | 917 | 659 | 342 | 82 | 9 | 4657 |
| GDD Base 45 |
0 | 1 | 33 | 144 | 420 | 684 | 831 | 762 | 510 | 218 | 40 | 3 | 3601 |
| GDD Base 50 |
0 | 0 | 15 | 78 | 282 | 535 | 676 | 607 | 366 | 124 | 17 | 1 | 2665 |
| GDD Base 55 |
0 | 0 | 6 | 39 | 169 | 389 | 521 | 453 | 237 | 60 | 5 | 0 | 1853 |
| GDD Base 60 |
0 | 0 | 1 | 18 | 91 | 252 | 367 | 304 | 136 | 23 | 0 | 0 | 1176 |
| MGDD* Base 50 |
0 | 4 | 43 | 157 | 356 | 542 | 658 | 606 | 413 | 207 | 45 | 4 | 2998 |
| 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 | 4/20 | 4/25 | 5/29 | 6/08 | 10/04 | 9/17 | 9/22 | 10/18 | 11/03 |
| 30 | 5/05 | 4/09 | 4/12 | 5/28 | 6/08 | 10/08 | 9/19 | 9/23 | 10/26 | 11/03 |
| 28 | 4/26 | 3/26 | 4/10 | 5/09 | 5/11 | 10/11 | 9/22 | 9/26 | 11/04 | 11/11 |
| 24 | 4/11 | 3/25 | 4/02 | 4/27 | 5/06 | 10/31 | 10/02 | 10/11 | 11/12 | 11/20 |
| 20 | 4/05 | 3/07 | 3/19 | 4/16 | 4/25 | 11/08 | 10/14 | 10/20 | 11/23 | 11/29 |
| 16 | 3/23 | 2/18 | 3/04 | 4/09 | 4/09 | 11/21 | 10/20 | 11/03 | 12/03 | 12/22 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 147 | 126 | 134 | 166 | 182 |
| 30 | 156 | 126 | 135 | 180 | 204 |
| 28 | 174 | 139 | 148 | 198 | 213 |
| 24 | 199 | 167 | 186 | 216 | 225 |
| 20 | 217 | 188 | 200 | 245 | 258 |
| 16 | 247 | 194 | 218 | 268 | 280 |