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 | 15 | 131 | 426 | 668 | 842 | 764 | 460 | 171 | 21 | 0 | 3433 |
| GDD Base 45 |
0 | 0 | 4 | 69 | 292 | 521 | 688 | 609 | 320 | 90 | 7 | 0 | 2548 |
| GDD Base 50 |
0 | 0 | 0 | 33 | 181 | 377 | 533 | 455 | 198 | 41 | 1 | 0 | 1783 |
| GDD Base 55 |
0 | 0 | 0 | 14 | 97 | 245 | 380 | 307 | 106 | 16 | 0 | 0 | 1142 |
| GDD Base 60 |
0 | 0 | 0 | 5 | 44 | 135 | 238 | 177 | 48 | 4 | 0 | 0 | 639 |
| MGDD* Base 50 |
0 | 1 | 14 | 112 | 293 | 428 | 543 | 489 | 292 | 119 | 15 | 0 | 2263 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/31 | 4/30 | 5/18 | 6/17 | 6/25 | 9/12 | 8/12 | 8/25 | 9/22 | 10/04 |
| 30 | 5/26 | 4/25 | 5/12 | 6/13 | 6/25 | 9/18 | 8/26 | 9/03 | 9/28 | 10/04 |
| 28 | 5/20 | 4/25 | 5/07 | 6/07 | 6/21 | 9/21 | 8/27 | 9/09 | 10/06 | 10/10 |
| 24 | 5/06 | 3/30 | 4/19 | 5/20 | 5/25 | 10/04 | 9/20 | 9/25 | 10/22 | 10/22 |
| 20 | 4/26 | 3/26 | 4/08 | 5/09 | 5/13 | 10/17 | 9/26 | 10/03 | 11/04 | 11/12 |
| 16 | 4/13 | 3/25 | 4/03 | 4/28 | 5/07 | 10/30 | 10/02 | 10/12 | 11/14 | 11/20 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 98 | 69 | 73 | 124 | 145 |
| 30 | 111 | 69 | 89 | 128 | 155 |
| 28 | 128 | 87 | 100 | 143 | 157 |
| 24 | 148 | 129 | 134 | 177 | 187 |
| 20 | 172 | 149 | 153 | 207 | 216 |
| 16 | 196 | 161 | 173 | 221 | 231 |