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 |
1 | 3 | 56 | 229 | 543 | 798 | 959 | 890 | 618 | 288 | 54 | 4 | 4434 |
| GDD Base 45 |
0 | 0 | 26 | 133 | 393 | 649 | 804 | 736 | 470 | 175 | 24 | 1 | 3405 |
| GDD Base 50 |
0 | 0 | 11 | 69 | 257 | 500 | 649 | 581 | 327 | 91 | 9 | 0 | 2489 |
| GDD Base 55 |
0 | 0 | 4 | 33 | 148 | 355 | 494 | 427 | 204 | 39 | 2 | 0 | 1701 |
| GDD Base 60 |
0 | 0 | 1 | 14 | 74 | 220 | 341 | 277 | 110 | 13 | 0 | 0 | 1047 |
| MGDD* Base 50 |
0 | 2 | 38 | 147 | 331 | 512 | 636 | 579 | 376 | 173 | 29 | 2 | 2821 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/05 | 4/21 | 4/23 | 5/20 | 5/28 | 10/04 | 9/20 | 9/22 | 10/12 | 10/17 |
| 30 | 5/02 | 4/09 | 4/13 | 5/12 | 5/16 | 10/05 | 9/20 | 9/23 | 10/14 | 11/03 |
| 28 | 4/24 | 4/02 | 4/10 | 5/07 | 5/16 | 10/09 | 9/22 | 9/25 | 11/01 | 11/09 |
| 24 | 4/10 | 3/23 | 3/28 | 4/22 | 5/07 | 10/25 | 10/02 | 10/09 | 11/14 | 11/19 |
| 20 | 4/06 | 3/18 | 3/22 | 4/18 | 4/21 | 11/03 | 10/10 | 10/15 | 11/19 | 11/25 |
| 16 | 3/24 | 2/21 | 3/03 | 4/09 | 4/13 | 11/11 | 10/20 | 10/31 | 11/27 | 12/20 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 153 | 125 | 134 | 160 | 167 |
| 30 | 157 | 138 | 143 | 177 | 204 |
| 28 | 167 | 140 | 151 | 191 | 205 |
| 24 | 200 | 150 | 177 | 217 | 220 |
| 20 | 212 | 177 | 194 | 230 | 246 |
| 16 | 230 | 194 | 209 | 270 | 279 |