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 | 52 | 222 | 551 | 800 | 961 | 876 | 615 | 301 | 64 | 5 | 4389 |
| GDD Base 45 |
0 | 0 | 24 | 128 | 402 | 651 | 806 | 722 | 467 | 183 | 28 | 2 | 3365 |
| GDD Base 50 |
0 | 0 | 10 | 68 | 267 | 502 | 651 | 569 | 326 | 97 | 11 | 0 | 2462 |
| GDD Base 55 |
0 | 0 | 3 | 31 | 157 | 356 | 496 | 416 | 202 | 43 | 2 | 0 | 1679 |
| GDD Base 60 |
0 | 0 | 0 | 12 | 82 | 223 | 342 | 267 | 108 | 15 | 0 | 0 | 1033 |
| MGDD* Base 50 |
0 | 2 | 33 | 137 | 333 | 510 | 637 | 568 | 377 | 181 | 34 | 2 | 2778 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/03 | 4/08 | 4/14 | 5/16 | 5/25 | 10/02 | 9/20 | 9/22 | 10/13 | 10/22 |
| 30 | 4/27 | 4/08 | 4/12 | 5/11 | 5/16 | 10/06 | 9/22 | 9/23 | 10/20 | 11/04 |
| 28 | 4/23 | 3/28 | 4/06 | 5/06 | 5/13 | 10/11 | 9/22 | 9/24 | 11/04 | 11/10 |
| 24 | 4/10 | 3/24 | 3/27 | 4/21 | 4/25 | 10/26 | 9/30 | 10/03 | 11/15 | 11/16 |
| 20 | 4/04 | 3/07 | 3/18 | 4/12 | 4/22 | 11/07 | 10/19 | 10/24 | 11/24 | 12/08 |
| 16 | 3/23 | 2/18 | 3/08 | 4/08 | 4/13 | 11/20 | 10/19 | 11/03 | 12/04 | 12/21 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 155 | 127 | 135 | 174 | 177 |
| 30 | 162 | 139 | 142 | 184 | 195 |
| 28 | 172 | 140 | 152 | 208 | 217 |
| 24 | 200 | 171 | 177 | 223 | 234 |
| 20 | 219 | 194 | 201 | 246 | 267 |
| 16 | 237 | 209 | 215 | 271 | 282 |