Growing Degree Day Averages
Derived from 1971-1997 Data
| Element | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN |
| GDD Base 40 |
0 | 1 | 12 | 123 | 419 | 630 | 766 | 715 | 447 | 176 | 18 | 0 | 3197 |
| GDD Base 45 |
0 | 0 | 3 | 67 | 283 | 481 | 614 | 562 | 308 | 92 | 5 | 0 | 2324 |
| GDD Base 50 |
0 | 0 | 0 | 33 | 173 | 336 | 461 | 410 | 190 | 41 | 1 | 0 | 1579 |
| GDD Base 55 |
0 | 0 | 0 | 15 | 93 | 206 | 311 | 265 | 100 | 14 | 0 | 0 | 958 |
| GDD Base 60 |
0 | 0 | 0 | 5 | 41 | 105 | 175 | 142 | 44 | 3 | 0 | 0 | 490 |
| MGDD* Base 50 |
0 | 1 | 16 | 112 | 303 | 413 | 496 | 463 | 280 | 119 | 12 | 0 | 2144 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 6/08 | 5/15 | 5/24 | 6/30 | 7/02 | 9/05 | 7/22 | 8/13 | 9/18 | 9/18 |
| 30 | 6/04 | 5/15 | 5/18 | 6/25 | 7/02 | 9/15 | 8/17 | 8/18 | 9/25 | 10/02 |
| 28 | 5/26 | 5/02 | 5/15 | 6/12 | 6/25 | 9/19 | 8/24 | 9/01 | 10/03 | 10/09 |
| 24 | 5/10 | 4/16 | 4/25 | 5/29 | 6/11 | 10/08 | 9/20 | 9/22 | 10/16 | 10/17 |
| 20 | 4/29 | 4/09 | 4/12 | 5/12 | 5/18 | 10/14 | 9/23 | 10/01 | 11/02 | 11/07 |
| 16 | 4/14 | 4/04 | 4/07 | 4/28 | 5/07 | 11/01 | 10/06 | 10/10 | 11/13 | 11/16 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 94 | 24 | 49 | 111 | 121 |
| 30 | 99 | 56 | 67 | 125 | 133 |
| 28 | 116 | 73 | 85 | 134 | 138 |
| 24 | 145 | 110 | 128 | 163 | 178 |
| 20 | 166 | 138 | 141 | 198 | 205 |
| 16 | 194 | 170 | 173 | 216 | 217 |