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 | 6 | 53 | 203 | 522 | 777 | 941 | 872 | 604 | 295 | 65 | 6 | 4346 |
| GDD Base 45 |
0 | 1 | 25 | 115 | 374 | 627 | 786 | 717 | 456 | 179 | 29 | 2 | 3315 |
| GDD Base 50 |
0 | 0 | 11 | 59 | 243 | 478 | 631 | 563 | 316 | 95 | 11 | 0 | 2410 |
| GDD Base 55 |
0 | 0 | 4 | 27 | 141 | 334 | 476 | 409 | 194 | 42 | 2 | 0 | 1633 |
| GDD Base 60 |
0 | 0 | 1 | 11 | 71 | 206 | 323 | 263 | 102 | 14 | 0 | 0 | 994 |
| MGDD* Base 50 |
0 | 3 | 34 | 132 | 322 | 496 | 619 | 568 | 374 | 178 | 35 | 3 | 2769 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/10 | 4/21 | 4/26 | 5/30 | 6/10 | 10/02 | 9/12 | 9/18 | 10/13 | 10/22 |
| 30 | 5/09 | 4/07 | 4/20 | 5/26 | 5/28 | 10/05 | 9/14 | 9/23 | 10/15 | 10/22 |
| 28 | 4/28 | 4/06 | 4/12 | 5/13 | 5/28 | 10/06 | 9/22 | 9/23 | 10/20 | 11/01 |
| 24 | 4/12 | 3/16 | 4/02 | 4/29 | 5/02 | 10/22 | 9/23 | 10/02 | 11/11 | 11/15 |
| 20 | 4/06 | 3/16 | 3/20 | 4/17 | 5/01 | 11/05 | 10/13 | 10/20 | 11/18 | 11/26 |
| 16 | 3/23 | 2/21 | 3/11 | 4/09 | 4/13 | 11/21 | 10/19 | 11/06 | 12/03 | 12/21 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 143 | 109 | 120 | 160 | 177 |
| 30 | 151 | 121 | 131 | 172 | 188 |
| 28 | 162 | 137 | 140 | 181 | 199 |
| 24 | 195 | 149 | 171 | 215 | 234 |
| 20 | 212 | 184 | 195 | 238 | 250 |
| 16 | 239 | 208 | 216 | 263 | 280 |