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 | 31 | 196 | 543 | 759 | 923 | 859 | 553 | 261 | 32 | 1 | 4105 |
| GDD Base 45 |
0 | 0 | 11 | 110 | 394 | 609 | 768 | 704 | 408 | 153 | 12 | 0 | 3130 |
| GDD Base 50 |
0 | 0 | 3 | 55 | 258 | 460 | 613 | 549 | 274 | 77 | 4 | 0 | 2265 |
| GDD Base 55 |
0 | 0 | 0 | 24 | 149 | 315 | 458 | 395 | 162 | 32 | 0 | 0 | 1517 |
| GDD Base 60 |
0 | 0 | 0 | 9 | 72 | 187 | 306 | 250 | 81 | 9 | 0 | 0 | 905 |
| MGDD* Base 50 |
0 | 0 | 20 | 133 | 340 | 484 | 608 | 558 | 335 | 153 | 18 | 0 | 2619 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/12 | 4/11 | 4/24 | 5/23 | 6/21 | 9/23 | 9/01 | 9/14 | 10/07 | 10/14 |
| 30 | 5/06 | 4/11 | 4/21 | 5/21 | 5/26 | 10/01 | 9/01 | 9/21 | 10/12 | 10/22 |
| 28 | 4/29 | 3/26 | 4/15 | 5/16 | 5/21 | 10/02 | 9/03 | 9/23 | 10/20 | 11/03 |
| 24 | 4/20 | 3/26 | 4/05 | 5/06 | 5/15 | 10/14 | 9/22 | 10/02 | 11/02 | 11/04 |
| 20 | 4/09 | 3/24 | 3/29 | 4/21 | 5/15 | 11/01 | 10/02 | 10/17 | 11/12 | 11/15 |
| 16 | 4/05 | 3/14 | 3/18 | 4/11 | 4/18 | 11/07 | 10/02 | 10/19 | 11/23 | 12/07 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 137 | 100 | 115 | 162 | 169 |
| 30 | 146 | 118 | 127 | 164 | 188 |
| 28 | 156 | 120 | 136 | 175 | 207 |
| 24 | 176 | 142 | 158 | 208 | 210 |
| 20 | 202 | 173 | 185 | 222 | 226 |
| 16 | 216 | 177 | 193 | 241 | 266 |