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 | 5 | 48 | 206 | 541 | 788 | 948 | 879 | 596 | 278 | 51 | 5 | 4257 |
| GDD Base 45 |
0 | 1 | 21 | 117 | 391 | 639 | 793 | 724 | 448 | 168 | 21 | 1 | 3255 |
| GDD Base 50 |
0 | 0 | 8 | 61 | 256 | 490 | 638 | 570 | 308 | 87 | 7 | 0 | 2369 |
| GDD Base 55 |
0 | 0 | 2 | 29 | 147 | 344 | 483 | 415 | 189 | 38 | 1 | 0 | 1610 |
| GDD Base 60 |
0 | 0 | 0 | 12 | 74 | 211 | 330 | 266 | 100 | 13 | 0 | 0 | 984 |
| MGDD* Base 50 |
0 | 3 | 36 | 143 | 338 | 504 | 629 | 574 | 365 | 173 | 31 | 3 | 2743 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/11 | 4/21 | 4/29 | 5/29 | 6/20 | 10/03 | 9/19 | 9/22 | 10/16 | 10/29 |
| 30 | 5/03 | 4/07 | 4/23 | 5/21 | 5/29 | 10/05 | 9/21 | 9/22 | 10/19 | 10/31 |
| 28 | 4/29 | 4/08 | 4/13 | 5/11 | 5/20 | 10/09 | 9/22 | 9/24 | 10/31 | 11/03 |
| 24 | 4/14 | 3/27 | 4/03 | 4/25 | 5/05 | 10/21 | 10/02 | 10/02 | 11/05 | 11/10 |
| 20 | 4/08 | 3/21 | 3/23 | 4/16 | 4/18 | 11/04 | 10/02 | 10/14 | 11/14 | 11/25 |
| 16 | 3/30 | 3/08 | 3/17 | 4/11 | 4/13 | 11/12 | 10/19 | 10/31 | 12/02 | 12/08 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 144 | 95 | 127 | 157 | 170 |
| 30 | 154 | 121 | 136 | 173 | 182 |
| 28 | 164 | 135 | 151 | 183 | 208 |
| 24 | 191 | 150 | 165 | 213 | 219 |
| 20 | 211 | 173 | 195 | 231 | 236 |
| 16 | 221 | 204 | 209 | 257 | 266 |