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 | 0 | 19 | 88 | 423 | 694 | 798 | 758 | 460 | 158 | 16 | 0 | 3411 |
| GDD Base 45 |
0 | 0 | 6 | 40 | 290 | 545 | 643 | 604 | 319 | 77 | 5 | 0 | 2527 |
| GDD Base 50 |
0 | 0 | 0 | 14 | 179 | 401 | 488 | 449 | 196 | 29 | 1 | 0 | 1759 |
| GDD Base 55 |
0 | 0 | 0 | 3 | 94 | 268 | 335 | 298 | 106 | 10 | 0 | 0 | 1115 |
| GDD Base 60 |
0 | 0 | 0 | 0 | 42 | 152 | 193 | 166 | 48 | 1 | 0 | 0 | 603 |
| MGDD* Base 50 |
0 | 0 | 15 | 69 | 262 | 431 | 498 | 469 | 266 | 95 | 9 | 0 | 2114 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/27 | 5/08 | 5/11 | 6/14 | 6/22 | 9/24 | 9/15 | 9/17 | 10/01 | 10/02 |
| 30 | 5/19 | 4/24 | 4/30 | 6/01 | 6/05 | 9/27 | 9/20 | 9/22 | 10/03 | 10/04 |
| 28 | 5/08 | 4/24 | 4/25 | 5/29 | 6/05 | 9/29 | 9/20 | 9/22 | 10/15 | 10/18 |
| 24 | 4/26 | 4/10 | 4/12 | 5/10 | 5/16 | 10/20 | 10/02 | 10/06 | 11/07 | 11/10 |
| 20 | 4/14 | 3/24 | 3/28 | 4/21 | 4/23 | 10/28 | 10/02 | 10/08 | 11/16 | 11/16 |
| 16 | 4/08 | 3/24 | 3/25 | 4/16 | 4/18 | 11/10 | 11/01 | 11/01 | 11/26 | 11/29 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 123 | 94 | 100 | 139 | 142 |
| 30 | 134 | 109 | 114 | 150 | 156 |
| 28 | 145 | 110 | 120 | 163 | 164 |
| 24 | 173 | 159 | 159 | 199 | 203 |
| 20 | 204 | 162 | 170 | 220 | 223 |
| 16 | 216 | 197 | 202 | 241 | 249 |