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 | 13 | 111 | 396 | 644 | 846 | 793 | 512 | 208 | 27 | 1 | 3390 |
| GDD Base 45 |
0 | 0 | 4 | 57 | 262 | 499 | 694 | 641 | 367 | 113 | 10 | 0 | 2528 |
| GDD Base 50 |
0 | 0 | 0 | 27 | 156 | 357 | 542 | 490 | 236 | 51 | 3 | 0 | 1782 |
| GDD Base 55 |
0 | 0 | 0 | 11 | 81 | 227 | 390 | 341 | 131 | 19 | 0 | 0 | 1152 |
| GDD Base 60 |
0 | 0 | 0 | 3 | 35 | 120 | 246 | 204 | 62 | 6 | 0 | 0 | 653 |
| MGDD* Base 50 |
0 | 1 | 13 | 91 | 263 | 403 | 543 | 506 | 311 | 133 | 18 | 0 | 2176 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/30 | 5/10 | 5/17 | 6/23 | 6/26 | 9/23 | 9/03 | 9/10 | 10/07 | 10/08 |
| 30 | 5/26 | 4/27 | 5/07 | 6/10 | 6/23 | 9/27 | 9/08 | 9/20 | 10/08 | 10/15 |
| 28 | 5/18 | 4/21 | 4/29 | 5/31 | 6/11 | 10/01 | 9/16 | 9/21 | 10/21 | 10/27 |
| 24 | 5/01 | 4/07 | 4/17 | 5/18 | 5/30 | 10/17 | 9/23 | 10/03 | 11/02 | 11/12 |
| 20 | 4/18 | 3/24 | 4/06 | 5/08 | 5/30 | 10/28 | 10/10 | 10/13 | 11/11 | 11/12 |
| 16 | 4/08 | 3/21 | 3/23 | 4/21 | 5/30 | 11/06 | 10/19 | 10/25 | 11/15 | 12/21 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 115 | 87 | 93 | 134 | 151 |
| 30 | 126 | 94 | 105 | 149 | 156 |
| 28 | 135 | 110 | 119 | 169 | 177 |
| 24 | 169 | 126 | 141 | 190 | 198 |
| 20 | 188 | 152 | 166 | 217 | 233 |
| 16 | 215 | 152 | 193 | 228 | 273 |