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 | 46 | 211 | 534 | 790 | 946 | 874 | 588 | 269 | 48 | 4 | 4199 |
| GDD Base 45 |
0 | 1 | 21 | 121 | 384 | 641 | 793 | 721 | 442 | 159 | 19 | 1 | 3215 |
| GDD Base 50 |
0 | 0 | 8 | 62 | 249 | 493 | 640 | 569 | 304 | 81 | 6 | 0 | 2343 |
| GDD Base 55 |
0 | 0 | 3 | 28 | 140 | 348 | 487 | 416 | 185 | 33 | 1 | 0 | 1592 |
| GDD Base 60 |
0 | 0 | 0 | 11 | 67 | 216 | 336 | 270 | 97 | 11 | 0 | 0 | 975 |
| MGDD* Base 50 |
0 | 2 | 34 | 147 | 335 | 509 | 625 | 570 | 367 | 174 | 33 | 2 | 2727 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/11 | 3/30 | 4/28 | 5/29 | 6/11 | 10/01 | 9/19 | 9/22 | 10/11 | 10/14 |
| 30 | 5/05 | 3/30 | 4/22 | 5/18 | 5/27 | 10/04 | 9/20 | 9/22 | 10/12 | 10/15 |
| 28 | 4/28 | 3/27 | 4/08 | 5/11 | 5/13 | 10/05 | 9/22 | 9/24 | 10/25 | 11/01 |
| 24 | 4/14 | 3/24 | 4/01 | 4/23 | 4/28 | 10/20 | 10/02 | 10/04 | 11/07 | 11/16 |
| 20 | 4/08 | 3/22 | 3/25 | 4/18 | 4/21 | 11/03 | 10/02 | 10/14 | 11/13 | 11/24 |
| 16 | 3/26 | 2/22 | 3/04 | 4/09 | 4/18 | 11/11 | 10/20 | 10/30 | 11/30 | 12/21 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 140 | 112 | 120 | 163 | 187 |
| 30 | 151 | 132 | 136 | 168 | 188 |
| 28 | 162 | 138 | 143 | 184 | 191 |
| 24 | 188 | 161 | 172 | 213 | 225 |
| 20 | 204 | 177 | 190 | 223 | 234 |
| 16 | 225 | 194 | 213 | 264 | 279 |