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 | 1 | 34 | 199 | 530 | 772 | 931 | 871 | 574 | 265 | 39 | 1 | 4193 |
| GDD Base 45 |
0 | 0 | 14 | 111 | 381 | 622 | 776 | 716 | 427 | 154 | 15 | 0 | 3196 |
| GDD Base 50 |
0 | 0 | 5 | 54 | 246 | 472 | 621 | 561 | 289 | 77 | 4 | 0 | 2314 |
| GDD Base 55 |
0 | 0 | 1 | 23 | 139 | 327 | 466 | 406 | 173 | 31 | 0 | 0 | 1556 |
| GDD Base 60 |
0 | 0 | 0 | 7 | 68 | 197 | 313 | 258 | 89 | 9 | 0 | 0 | 935 |
| MGDD* Base 50 |
0 | 0 | 23 | 135 | 332 | 492 | 611 | 564 | 352 | 161 | 22 | 1 | 2680 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/13 | 4/17 | 4/27 | 5/26 | 6/11 | 9/25 | 9/04 | 9/20 | 10/10 | 10/22 |
| 30 | 5/06 | 4/04 | 4/20 | 5/16 | 5/26 | 10/03 | 9/18 | 9/21 | 10/14 | 10/22 |
| 28 | 4/30 | 3/24 | 4/06 | 5/15 | 5/26 | 10/06 | 9/20 | 9/23 | 10/22 | 11/01 |
| 24 | 4/13 | 3/24 | 3/31 | 4/27 | 5/07 | 10/19 | 9/22 | 10/03 | 11/12 | 11/16 |
| 20 | 4/07 | 3/18 | 3/21 | 4/15 | 4/18 | 11/03 | 9/29 | 10/13 | 11/14 | 11/22 |
| 16 | 4/01 | 3/06 | 3/15 | 4/12 | 4/16 | 11/12 | 10/18 | 10/26 | 11/27 | 12/20 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 138 | 104 | 120 | 157 | 177 |
| 30 | 151 | 128 | 133 | 174 | 181 |
| 28 | 160 | 128 | 138 | 188 | 212 |
| 24 | 190 | 150 | 158 | 217 | 233 |
| 20 | 211 | 177 | 190 | 229 | 242 |
| 16 | 222 | 194 | 208 | 255 | 278 |