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 | 4 | 47 | 193 | 503 | 766 | 941 | 884 | 620 | 311 | 65 | 6 | 4294 |
| GDD Base 45 |
0 | 1 | 23 | 107 | 356 | 617 | 787 | 729 | 472 | 189 | 28 | 2 | 3274 |
| GDD Base 50 |
0 | 0 | 10 | 53 | 227 | 468 | 633 | 575 | 329 | 101 | 10 | 0 | 2377 |
| GDD Base 55 |
0 | 0 | 3 | 23 | 129 | 325 | 479 | 420 | 202 | 45 | 2 | 0 | 1609 |
| GDD Base 60 |
0 | 0 | 0 | 10 | 66 | 197 | 326 | 271 | 107 | 15 | 0 | 0 | 982 |
| MGDD* Base 50 |
0 | 2 | 30 | 117 | 304 | 484 | 623 | 575 | 375 | 171 | 32 | 3 | 2687 |
| 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 | 4/18 | 4/26 | 5/27 | 6/01 | 10/03 | 9/16 | 9/22 | 10/19 | 11/03 |
| 30 | 5/02 | 4/08 | 4/15 | 5/22 | 5/27 | 10/06 | 9/16 | 9/23 | 11/02 | 11/04 |
| 28 | 4/26 | 3/27 | 4/10 | 5/12 | 5/16 | 10/17 | 9/22 | 9/26 | 11/04 | 11/12 |
| 24 | 4/10 | 3/24 | 3/30 | 4/29 | 5/16 | 11/02 | 10/13 | 10/17 | 11/14 | 11/19 |
| 20 | 4/04 | 3/14 | 3/18 | 4/11 | 4/18 | 11/08 | 10/13 | 10/20 | 11/20 | 11/26 |
| 16 | 3/22 | 2/27 | 3/10 | 4/06 | 4/09 | 11/21 | 10/31 | 11/07 | 12/02 | 12/07 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 148 | 121 | 129 | 167 | 177 |
| 30 | 159 | 121 | 137 | 182 | 203 |
| 28 | 174 | 138 | 142 | 200 | 210 |
| 24 | 206 | 171 | 182 | 220 | 228 |
| 20 | 219 | 190 | 199 | 242 | 247 |
| 16 | 241 | 218 | 219 | 263 | 268 |