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 |
2 | 7 | 48 | 172 | 454 | 744 | 960 | 945 | 685 | 357 | 95 | 11 | 4329 |
| GDD Base 45 |
0 | 1 | 22 | 88 | 306 | 596 | 806 | 791 | 536 | 224 | 42 | 3 | 3288 |
| GDD Base 50 |
0 | 0 | 8 | 40 | 181 | 448 | 652 | 637 | 391 | 120 | 16 | 0 | 2392 |
| GDD Base 55 |
0 | 0 | 2 | 16 | 94 | 306 | 498 | 483 | 254 | 51 | 4 | 0 | 1634 |
| GDD Base 60 |
0 | 0 | 0 | 5 | 43 | 183 | 345 | 330 | 140 | 16 | 0 | 0 | 1012 |
| MGDD* Base 50 |
1 | 3 | 28 | 82 | 224 | 450 | 638 | 629 | 404 | 168 | 37 | 5 | 2568 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 4/23 | 4/06 | 4/09 | 5/09 | 5/13 | 10/19 | 10/04 | 10/08 | 11/04 | 11/18 |
| 30 | 4/20 | 3/24 | 4/05 | 5/07 | 5/13 | 11/01 | 10/10 | 10/18 | 11/14 | 11/20 |
| 28 | 4/10 | 3/22 | 3/27 | 4/24 | 4/29 | 11/03 | 10/16 | 10/23 | 11/15 | 11/20 |
| 24 | 4/05 | 3/08 | 3/14 | 4/12 | 4/24 | 11/10 | 10/20 | 10/31 | 11/26 | 12/21 |
| 20 | 3/21 | 2/17 | 3/06 | 4/08 | 4/11 | 11/21 | 11/03 | 11/07 | 12/10 | 12/21 |
| 16 | 3/16 | 2/10 | 2/20 | 4/02 | 4/07 | 11/25 | 11/03 | 11/09 | 12/17 | 12/24 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 180 | 150 | 166 | 202 | 225 |
| 30 | 193 | 165 | 174 | 222 | 225 |
| 28 | 207 | 189 | 193 | 225 | 234 |
| 24 | 221 | 193 | 208 | 256 | 282 |
| 20 | 241 | 218 | 219 | 276 | 284 |
| 16 | 262 | 222 | 231 | 284 | 286 |