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 | 0 | 28 | 187 | 525 | 755 | 918 | 843 | 548 | 238 | 26 | 1 | 3989 |
| GDD Base 45 |
0 | 0 | 10 | 104 | 378 | 606 | 764 | 688 | 403 | 134 | 9 | 0 | 3036 |
| GDD Base 50 |
0 | 0 | 3 | 52 | 247 | 457 | 609 | 534 | 268 | 63 | 3 | 0 | 2193 |
| GDD Base 55 |
0 | 0 | 0 | 23 | 141 | 313 | 454 | 381 | 157 | 24 | 0 | 0 | 1468 |
| GDD Base 60 |
0 | 0 | 0 | 9 | 69 | 186 | 303 | 236 | 79 | 7 | 0 | 0 | 874 |
| MGDD* Base 50 |
0 | 0 | 18 | 132 | 328 | 482 | 604 | 544 | 332 | 144 | 17 | 0 | 2551 |
| 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 | 4/15 | 4/26 | 6/03 | 6/21 | 9/25 | 9/01 | 9/15 | 10/08 | 10/14 |
| 30 | 5/07 | 4/11 | 4/20 | 5/23 | 6/12 | 9/27 | 9/03 | 9/20 | 10/10 | 10/16 |
| 28 | 4/29 | 3/30 | 4/08 | 5/18 | 6/11 | 10/05 | 9/03 | 9/22 | 10/18 | 10/22 |
| 24 | 4/18 | 3/24 | 4/04 | 5/06 | 5/11 | 10/17 | 9/22 | 9/30 | 11/04 | 11/10 |
| 20 | 4/09 | 3/15 | 3/24 | 4/25 | 4/27 | 11/02 | 10/02 | 10/11 | 11/14 | 12/01 |
| 16 | 4/06 | 3/13 | 3/16 | 4/17 | 4/24 | 11/07 | 10/02 | 10/21 | 11/25 | 12/04 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 138 | 100 | 111 | 157 | 162 |
| 30 | 146 | 103 | 121 | 165 | 172 |
| 28 | 162 | 112 | 127 | 180 | 195 |
| 24 | 189 | 139 | 145 | 208 | 226 |
| 20 | 210 | 160 | 175 | 228 | 243 |
| 16 | 218 | 161 | 192 | 248 | 261 |