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 | 20 | 149 | 460 | 699 | 848 | 778 | 477 | 190 | 27 | 1 | 3555 |
| GDD Base 45 |
0 | 0 | 7 | 80 | 319 | 550 | 694 | 624 | 336 | 102 | 9 | 0 | 2651 |
| GDD Base 50 |
0 | 0 | 2 | 38 | 198 | 404 | 541 | 471 | 212 | 45 | 2 | 0 | 1862 |
| GDD Base 55 |
0 | 0 | 0 | 17 | 108 | 267 | 388 | 322 | 116 | 17 | 0 | 0 | 1201 |
| GDD Base 60 |
0 | 0 | 0 | 6 | 50 | 152 | 242 | 185 | 54 | 5 | 0 | 0 | 676 |
| MGDD* Base 50 |
0 | 0 | 17 | 113 | 300 | 443 | 547 | 496 | 296 | 124 | 18 | 0 | 2297 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/26 | 4/29 | 5/07 | 6/12 | 6/21 | 9/23 | 8/02 | 9/07 | 10/02 | 10/03 |
| 30 | 5/16 | 4/25 | 5/04 | 6/01 | 6/11 | 9/24 | 9/07 | 9/13 | 10/05 | 10/10 |
| 28 | 5/07 | 4/22 | 4/26 | 5/26 | 6/11 | 10/02 | 9/09 | 9/19 | 10/10 | 10/22 |
| 24 | 4/25 | 3/25 | 4/05 | 5/06 | 5/12 | 10/13 | 9/20 | 10/01 | 11/01 | 11/03 |
| 20 | 4/13 | 3/25 | 4/03 | 4/22 | 5/06 | 11/01 | 9/24 | 10/10 | 11/13 | 11/15 |
| 16 | 4/09 | 3/15 | 3/23 | 4/18 | 4/22 | 11/07 | 10/19 | 10/22 | 11/24 | 11/30 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 120 | 69 | 93 | 140 | 147 |
| 30 | 132 | 104 | 112 | 149 | 157 |
| 28 | 145 | 112 | 126 | 159 | 168 |
| 24 | 174 | 135 | 153 | 197 | 211 |
| 20 | 200 | 141 | 177 | 217 | 233 |
| 16 | 215 | 189 | 195 | 239 | 260 |