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 | 1 | 22 | 138 | 460 | 696 | 856 | 771 | 482 | 189 | 19 | 0 | 3322 |
| GDD Base 45 |
0 | 0 | 7 | 72 | 320 | 546 | 701 | 616 | 339 | 100 | 7 | 0 | 2466 |
| GDD Base 50 |
0 | 0 | 2 | 34 | 201 | 399 | 546 | 461 | 212 | 44 | 2 | 0 | 1727 |
| GDD Base 55 |
0 | 0 | 0 | 14 | 111 | 260 | 392 | 309 | 117 | 15 | 0 | 0 | 1106 |
| GDD Base 60 |
0 | 0 | 0 | 5 | 54 | 145 | 244 | 173 | 55 | 4 | 0 | 0 | 617 |
| MGDD* Base 50 |
0 | 0 | 16 | 96 | 280 | 427 | 549 | 477 | 275 | 105 | 10 | 0 | 2046 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/16 | 4/28 | 5/02 | 5/31 | 6/11 | 9/23 | 9/03 | 9/09 | 10/07 | 10/08 |
| 30 | 5/04 | 4/21 | 4/27 | 5/16 | 5/26 | 10/01 | 9/03 | 9/20 | 10/12 | 10/16 |
| 28 | 4/29 | 4/04 | 4/22 | 5/12 | 5/17 | 10/04 | 9/20 | 9/23 | 10/14 | 10/25 |
| 24 | 4/23 | 3/25 | 4/04 | 5/02 | 5/06 | 10/21 | 10/02 | 10/04 | 11/11 | 12/01 |
| 20 | 4/09 | 3/24 | 3/26 | 4/22 | 5/06 | 11/01 | 10/13 | 10/19 | 11/12 | 12/01 |
| 16 | 4/04 | 3/16 | 3/22 | 4/10 | 4/11 | 11/11 | 10/19 | 10/30 | 11/29 | 12/09 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 127 | 104 | 109 | 150 | 158 |
| 30 | 149 | 113 | 133 | 163 | 170 |
| 28 | 157 | 136 | 141 | 174 | 181 |
| 24 | 186 | 151 | 164 | 211 | 217 |
| 20 | 208 | 166 | 187 | 220 | 250 |
| 16 | 218 | 193 | 211 | 249 | 268 |