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 | 50 | 251 | 569 | 804 | 967 | 897 | 601 | 306 | 48 | 2 | 4388 |
| GDD Base 45 |
0 | 0 | 22 | 150 | 421 | 657 | 814 | 745 | 457 | 190 | 20 | 1 | 3398 |
| GDD Base 50 |
0 | 0 | 9 | 80 | 282 | 511 | 662 | 593 | 320 | 105 | 7 | 0 | 2516 |
| GDD Base 55 |
0 | 0 | 3 | 39 | 167 | 366 | 509 | 441 | 201 | 48 | 2 | 0 | 1743 |
| GDD Base 60 |
0 | 0 | 0 | 16 | 85 | 232 | 357 | 293 | 110 | 17 | 0 | 0 | 1095 |
| MGDD* Base 50 |
0 | 2 | 35 | 174 | 364 | 524 | 649 | 594 | 375 | 193 | 29 | 2 | 2872 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/16 | 4/24 | 4/29 | 5/29 | 6/22 | 10/01 | 9/03 | 9/20 | 10/09 | 10/15 |
| 30 | 5/04 | 4/08 | 4/24 | 5/19 | 5/21 | 10/03 | 9/20 | 9/21 | 10/10 | 10/15 |
| 28 | 5/01 | 3/29 | 4/08 | 5/14 | 5/17 | 10/06 | 9/20 | 9/26 | 10/21 | 11/02 |
| 24 | 4/13 | 3/24 | 4/02 | 5/01 | 5/06 | 10/19 | 10/02 | 10/04 | 11/05 | 12/01 |
| 20 | 4/09 | 3/22 | 3/25 | 4/17 | 4/21 | 10/28 | 10/02 | 10/10 | 11/13 | 12/01 |
| 16 | 4/04 | 3/07 | 3/18 | 4/10 | 4/20 | 11/09 | 10/11 | 10/20 | 11/26 | 12/07 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 139 | 100 | 121 | 154 | 159 |
| 30 | 149 | 128 | 139 | 163 | 178 |
| 28 | 159 | 141 | 144 | 185 | 193 |
| 24 | 189 | 151 | 162 | 212 | 217 |
| 20 | 206 | 174 | 179 | 228 | 242 |
| 16 | 219 | 190 | 200 | 246 | 261 |