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 | 3 | 42 | 243 | 579 | 815 | 985 | 914 | 621 | 307 | 49 | 2 | 4557 |
| GDD Base 45 |
0 | 0 | 18 | 141 | 427 | 665 | 830 | 759 | 474 | 189 | 19 | 0 | 3523 |
| GDD Base 50 |
0 | 0 | 6 | 72 | 286 | 516 | 675 | 604 | 334 | 100 | 6 | 0 | 2601 |
| GDD Base 55 |
0 | 0 | 1 | 33 | 170 | 369 | 520 | 449 | 210 | 43 | 1 | 0 | 1800 |
| GDD Base 60 |
0 | 0 | 0 | 13 | 86 | 233 | 367 | 299 | 114 | 14 | 0 | 0 | 1129 |
| MGDD* Base 50 |
0 | 2 | 32 | 171 | 367 | 528 | 657 | 603 | 387 | 191 | 32 | 1 | 2970 |
| 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 | 4/21 | 4/28 | 5/27 | 6/01 | 9/30 | 9/03 | 9/20 | 10/08 | 10/15 |
| 30 | 5/05 | 4/09 | 4/24 | 5/17 | 6/01 | 10/04 | 9/11 | 9/23 | 10/15 | 10/30 |
| 28 | 4/27 | 3/29 | 4/09 | 5/08 | 5/14 | 10/05 | 9/19 | 9/28 | 10/24 | 11/04 |
| 24 | 4/14 | 3/24 | 4/03 | 4/25 | 5/06 | 10/23 | 10/02 | 10/04 | 11/05 | 11/11 |
| 20 | 4/09 | 3/21 | 3/23 | 4/16 | 4/22 | 11/03 | 10/02 | 10/19 | 11/12 | 11/16 |
| 16 | 3/26 | 2/26 | 3/11 | 4/07 | 4/09 | 11/12 | 10/20 | 10/30 | 11/29 | 12/19 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 141 | 102 | 120 | 157 | 169 |
| 30 | 156 | 102 | 135 | 168 | 176 |
| 28 | 164 | 143 | 147 | 186 | 195 |
| 24 | 192 | 151 | 164 | 208 | 226 |
| 20 | 210 | 177 | 190 | 225 | 233 |
| 16 | 231 | 194 | 212 | 259 | 274 |