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 | 4 | 45 | 181 | 479 | 742 | 916 | 860 | 601 | 284 | 67 | 6 | 4191 |
| GDD Base 45 |
0 | 0 | 21 | 101 | 335 | 593 | 762 | 706 | 454 | 170 | 30 | 2 | 3177 |
| GDD Base 50 |
0 | 0 | 8 | 53 | 212 | 445 | 608 | 552 | 313 | 91 | 11 | 0 | 2297 |
| GDD Base 55 |
0 | 0 | 3 | 26 | 119 | 304 | 454 | 399 | 193 | 39 | 3 | 0 | 1544 |
| GDD Base 60 |
0 | 0 | 0 | 11 | 60 | 183 | 304 | 254 | 104 | 13 | 0 | 0 | 934 |
| MGDD* Base 50 |
0 | 2 | 29 | 112 | 289 | 467 | 602 | 557 | 367 | 168 | 37 | 3 | 2638 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/17 | 4/25 | 4/29 | 5/30 | 6/12 | 9/30 | 9/05 | 9/19 | 10/11 | 10/17 |
| 30 | 5/10 | 4/21 | 4/25 | 5/27 | 6/04 | 10/04 | 9/05 | 9/23 | 10/18 | 11/03 |
| 28 | 5/04 | 4/02 | 4/17 | 5/16 | 6/04 | 10/10 | 9/05 | 9/23 | 10/22 | 11/04 |
| 24 | 4/14 | 3/26 | 4/05 | 5/04 | 5/11 | 10/30 | 9/30 | 10/11 | 11/12 | 11/20 |
| 20 | 4/08 | 3/16 | 3/20 | 4/20 | 4/29 | 11/04 | 10/10 | 10/17 | 11/20 | 11/29 |
| 16 | 3/24 | 3/02 | 3/05 | 4/09 | 4/18 | 11/19 | 10/18 | 10/27 | 12/05 | 12/21 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 138 | 110 | 119 | 156 | 160 |
| 30 | 145 | 119 | 126 | 172 | 182 |
| 28 | 160 | 125 | 135 | 182 | 191 |
| 24 | 193 | 149 | 173 | 216 | 225 |
| 20 | 208 | 186 | 191 | 243 | 248 |
| 16 | 239 | 199 | 214 | 262 | 280 |