Growing Degree Day Averages
Derived from 1971-1998 Data
| Element | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN |
| GDD Base 40 |
0 | 1 | 20 | 159 | 469 | 729 | 891 | 825 | 533 | 231 | 32 | 0 | 3892 |
| GDD Base 45 |
0 | 0 | 6 | 87 | 325 | 579 | 736 | 670 | 387 | 131 | 11 | 0 | 2935 |
| GDD Base 50 |
0 | 0 | 1 | 43 | 202 | 430 | 581 | 515 | 252 | 63 | 3 | 0 | 2095 |
| GDD Base 55 |
0 | 0 | 0 | 20 | 111 | 288 | 426 | 362 | 142 | 25 | 0 | 0 | 1382 |
| GDD Base 60 |
0 | 0 | 0 | 7 | 53 | 165 | 276 | 219 | 66 | 7 | 0 | 0 | 802 |
| MGDD* Base 50 |
0 | 0 | 17 | 124 | 316 | 466 | 581 | 535 | 333 | 151 | 20 | 0 | 2550 |
| 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 | 5/02 | 5/06 | 6/09 | 7/06 | 9/24 | 8/16 | 9/04 | 10/04 | 10/15 |
| 30 | 5/18 | 5/02 | 5/05 | 6/09 | 7/05 | 9/24 | 9/03 | 9/04 | 10/13 | 10/17 |
| 28 | 5/10 | 4/17 | 4/26 | 6/03 | 7/05 | 10/03 | 9/03 | 9/14 | 10/13 | 10/21 |
| 24 | 4/24 | 4/05 | 4/09 | 5/13 | 5/15 | 10/13 | 9/20 | 9/24 | 10/30 | 11/10 |
| 20 | 4/15 | 4/02 | 4/04 | 5/06 | 5/13 | 11/01 | 9/23 | 10/02 | 11/12 | 11/16 |
| 16 | 4/08 | 3/16 | 3/19 | 4/21 | 5/07 | 11/09 | 9/23 | 10/19 | 11/22 | 12/02 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 121 | 60 | 82 | 141 | 146 |
| 30 | 133 | 61 | 99 | 143 | 152 |
| 28 | 146 | 80 | 111 | 159 | 161 |
| 24 | 171 | 128 | 135 | 202 | 205 |
| 20 | 190 | 135 | 164 | 216 | 223 |
| 16 | 218 | 139 | 189 | 238 | 249 |