Growing Degree Day Averages
Derived from 1971-1987 Data
| Element | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN |
| GDD Base 40 |
0 | 2 | 37 | 214 | 513 | 733 | 916 | 846 | 565 | 281 | 48 | 2 | 4074 |
| GDD Base 45 |
0 | 0 | 17 | 125 | 366 | 583 | 762 | 691 | 418 | 167 | 19 | 0 | 3087 |
| GDD Base 50 |
0 | 0 | 6 | 66 | 234 | 434 | 608 | 536 | 282 | 84 | 5 | 0 | 2213 |
| GDD Base 55 |
0 | 0 | 1 | 32 | 130 | 289 | 454 | 382 | 169 | 36 | 1 | 0 | 1472 |
| GDD Base 60 |
0 | 0 | 0 | 14 | 63 | 164 | 304 | 237 | 86 | 11 | 0 | 0 | 870 |
| MGDD* Base 50 |
0 | 2 | 27 | 152 | 337 | 473 | 604 | 553 | 357 | 177 | 31 | 1 | 2663 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/17 | 5/01 | 5/02 | 5/28 | 5/31 | 9/21 | 9/01 | 9/08 | 9/28 | 10/03 |
| 30 | 5/13 | 4/21 | 4/28 | 5/25 | 5/27 | 9/24 | 9/04 | 9/13 | 10/08 | 10/16 |
| 28 | 5/09 | 4/08 | 4/22 | 5/19 | 5/27 | 9/29 | 9/20 | 9/22 | 10/13 | 10/16 |
| 24 | 4/21 | 4/08 | 4/08 | 5/05 | 5/06 | 10/14 | 9/22 | 9/26 | 11/01 | 11/02 |
| 20 | 4/08 | 3/25 | 3/26 | 4/22 | 4/24 | 10/30 | 9/22 | 10/10 | 11/11 | 11/12 |
| 16 | 4/05 | 3/16 | 3/23 | 4/14 | 4/22 | 11/11 | 10/18 | 10/20 | 11/20 | 11/22 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 125 | 109 | 111 | 143 | 146 |
| 30 | 137 | 114 | 117 | 155 | 171 |
| 28 | 148 | 126 | 131 | 170 | 171 |
| 24 | 179 | 139 | 143 | 188 | 201 |
| 20 | 201 | 151 | 179 | 221 | 223 |
| 16 | 221 | 194 | 195 | 236 | 237 |