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 |
0 | 2 | 33 | 177 | 506 | 766 | 937 | 868 | 584 | 266 | 46 | 3 | 4193 |
| GDD Base 45 |
0 | 0 | 14 | 94 | 358 | 616 | 782 | 713 | 436 | 154 | 18 | 1 | 3190 |
| GDD Base 50 |
0 | 0 | 5 | 46 | 227 | 466 | 627 | 558 | 295 | 76 | 5 | 0 | 2310 |
| GDD Base 55 |
0 | 0 | 2 | 21 | 127 | 322 | 472 | 404 | 176 | 31 | 1 | 0 | 1558 |
| GDD Base 60 |
0 | 0 | 0 | 8 | 62 | 195 | 319 | 254 | 89 | 9 | 0 | 0 | 939 |
| MGDD* Base 50 |
0 | 0 | 21 | 111 | 303 | 480 | 617 | 561 | 345 | 145 | 24 | 1 | 2612 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/06 | 4/17 | 4/23 | 5/17 | 5/26 | 10/03 | 9/20 | 9/21 | 10/15 | 10/27 |
| 30 | 5/03 | 4/07 | 4/17 | 5/14 | 5/16 | 10/07 | 9/20 | 9/23 | 10/20 | 11/06 |
| 28 | 4/26 | 4/06 | 4/10 | 5/07 | 5/09 | 10/13 | 9/21 | 9/25 | 11/03 | 11/10 |
| 24 | 4/10 | 3/24 | 3/29 | 4/21 | 4/25 | 11/02 | 10/07 | 10/16 | 11/12 | 11/16 |
| 20 | 4/05 | 3/13 | 3/18 | 4/11 | 4/18 | 11/09 | 10/20 | 10/26 | 11/19 | 11/26 |
| 16 | 3/24 | 2/27 | 3/12 | 4/06 | 4/09 | 11/20 | 10/31 | 11/07 | 12/05 | 12/21 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 152 | 128 | 134 | 169 | 182 |
| 30 | 160 | 133 | 141 | 177 | 198 |
| 28 | 172 | 137 | 153 | 197 | 212 |
| 24 | 202 | 174 | 187 | 221 | 233 |
| 20 | 222 | 194 | 207 | 235 | 241 |
| 16 | 242 | 217 | 219 | 265 | 280 |