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 | 5 | 59 | 235 | 572 | 819 | 981 | 903 | 637 | 327 | 65 | 6 | 4607 |
| GDD Base 45 |
0 | 1 | 30 | 138 | 421 | 671 | 826 | 751 | 490 | 206 | 29 | 2 | 3562 |
| GDD Base 50 |
0 | 0 | 15 | 73 | 282 | 522 | 671 | 599 | 348 | 114 | 10 | 0 | 2633 |
| GDD Base 55 |
0 | 0 | 6 | 33 | 168 | 376 | 516 | 447 | 222 | 52 | 2 | 0 | 1824 |
| GDD Base 60 |
0 | 0 | 1 | 14 | 86 | 240 | 362 | 298 | 123 | 19 | 0 | 0 | 1146 |
| MGDD* Base 50 |
0 | 3 | 39 | 155 | 360 | 531 | 656 | 598 | 396 | 193 | 34 | 3 | 2968 |
| 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 | 4/23 | 4/28 | 5/28 | 5/31 | 9/27 | 9/07 | 9/21 | 10/08 | 10/17 |
| 30 | 5/05 | 4/10 | 4/25 | 5/21 | 5/31 | 10/05 | 9/19 | 9/23 | 10/14 | 10/17 |
| 28 | 4/28 | 3/26 | 4/09 | 5/11 | 5/26 | 10/06 | 9/22 | 9/25 | 10/26 | 11/03 |
| 24 | 4/13 | 3/24 | 4/03 | 4/30 | 5/09 | 10/23 | 9/22 | 10/04 | 11/08 | 11/11 |
| 20 | 4/08 | 3/22 | 3/24 | 4/16 | 4/22 | 11/03 | 10/10 | 10/20 | 11/13 | 11/16 |
| 16 | 4/01 | 3/06 | 3/15 | 4/12 | 4/18 | 11/13 | 10/20 | 11/01 | 11/28 | 12/21 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 139 | 110 | 120 | 156 | 157 |
| 30 | 152 | 126 | 136 | 168 | 179 |
| 28 | 166 | 133 | 142 | 183 | 204 |
| 24 | 191 | 150 | 162 | 213 | 217 |
| 20 | 212 | 190 | 194 | 224 | 236 |
| 16 | 227 | 194 | 206 | 259 | 280 |