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 | 29 | 184 | 507 | 717 | 874 | 809 | 529 | 223 | 27 | 0 | 3907 |
| GDD Base 45 |
0 | 0 | 10 | 97 | 361 | 570 | 720 | 656 | 385 | 125 | 9 | 0 | 2938 |
| GDD Base 50 |
0 | 0 | 3 | 46 | 229 | 424 | 566 | 502 | 251 | 57 | 2 | 0 | 2086 |
| GDD Base 55 |
0 | 0 | 0 | 19 | 126 | 284 | 412 | 350 | 143 | 22 | 0 | 0 | 1361 |
| GDD Base 60 |
0 | 0 | 0 | 7 | 58 | 161 | 263 | 210 | 68 | 6 | 0 | 0 | 774 |
| MGDD* Base 50 |
0 | 1 | 27 | 145 | 335 | 461 | 569 | 522 | 332 | 152 | 20 | 0 | 2569 |
| 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 | 4/24 | 5/06 | 6/14 | 6/22 | 9/22 | 8/26 | 9/12 | 10/04 | 10/10 |
| 30 | 5/16 | 4/13 | 4/26 | 6/12 | 6/22 | 9/24 | 8/27 | 9/12 | 10/09 | 10/15 |
| 28 | 5/09 | 3/30 | 4/22 | 6/03 | 6/16 | 10/02 | 8/27 | 9/18 | 10/14 | 10/21 |
| 24 | 4/21 | 3/23 | 4/07 | 5/08 | 6/01 | 10/08 | 9/15 | 9/25 | 11/03 | 11/16 |
| 20 | 4/10 | 3/23 | 3/26 | 5/05 | 5/10 | 10/19 | 10/01 | 10/02 | 11/10 | 11/16 |
| 16 | 4/06 | 3/15 | 3/20 | 4/13 | 4/21 | 11/01 | 10/11 | 10/14 | 11/20 | 11/30 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 118 | 71 | 90 | 145 | 150 |
| 30 | 136 | 72 | 96 | 160 | 164 |
| 28 | 149 | 72 | 120 | 167 | 195 |
| 24 | 168 | 106 | 142 | 211 | 226 |
| 20 | 189 | 151 | 162 | 220 | 226 |
| 16 | 209 | 179 | 190 | 242 | 253 |