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 | 5 | 64 | 245 | 576 | 831 | 979 | 922 | 643 | 319 | 63 | 5 | 4546 |
| GDD Base 45 |
0 | 0 | 31 | 144 | 424 | 681 | 824 | 767 | 495 | 199 | 27 | 1 | 3508 |
| GDD Base 50 |
0 | 0 | 13 | 75 | 283 | 532 | 669 | 612 | 353 | 110 | 10 | 0 | 2588 |
| GDD Base 55 |
0 | 0 | 4 | 34 | 167 | 384 | 514 | 457 | 225 | 50 | 2 | 0 | 1790 |
| GDD Base 60 |
0 | 0 | 1 | 14 | 84 | 245 | 360 | 305 | 126 | 17 | 0 | 0 | 1120 |
| MGDD* Base 50 |
0 | 3 | 38 | 148 | 341 | 536 | 655 | 606 | 390 | 182 | 32 | 2 | 2866 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 4/30 | 4/05 | 4/12 | 5/11 | 5/14 | 10/06 | 9/20 | 9/23 | 10/17 | 10/31 |
| 30 | 4/21 | 3/25 | 4/05 | 5/08 | 5/08 | 10/08 | 9/23 | 9/27 | 10/28 | 11/04 |
| 28 | 4/17 | 3/25 | 4/01 | 4/29 | 5/07 | 10/17 | 9/29 | 10/04 | 11/04 | 11/04 |
| 24 | 4/10 | 3/21 | 3/25 | 4/18 | 4/23 | 10/31 | 10/08 | 10/14 | 11/10 | 11/14 |
| 20 | 4/02 | 3/07 | 3/15 | 4/11 | 4/18 | 11/06 | 10/20 | 10/25 | 11/21 | 11/30 |
| 16 | 3/21 | 2/21 | 3/04 | 4/07 | 4/09 | 11/16 | 10/20 | 11/04 | 12/06 | 12/21 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 161 | 137 | 145 | 175 | 181 |
| 30 | 171 | 140 | 153 | 200 | 211 |
| 28 | 183 | 149 | 165 | 208 | 224 |
| 24 | 203 | 179 | 187 | 221 | 227 |
| 20 | 219 | 194 | 203 | 251 | 261 |
| 16 | 241 | 194 | 217 | 272 | 281 |