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 | 2 | 37 | 195 | 552 | 804 | 986 | 913 | 628 | 289 | 52 | 2 | 4464 |
| GDD Base 45 |
0 | 0 | 15 | 107 | 402 | 655 | 831 | 758 | 480 | 171 | 21 | 0 | 3447 |
| GDD Base 50 |
0 | 0 | 6 | 53 | 266 | 505 | 676 | 603 | 337 | 87 | 7 | 0 | 2547 |
| GDD Base 55 |
0 | 0 | 1 | 24 | 158 | 359 | 522 | 448 | 211 | 36 | 1 | 0 | 1765 |
| GDD Base 60 |
0 | 0 | 0 | 10 | 85 | 226 | 368 | 296 | 114 | 11 | 0 | 0 | 1113 |
| MGDD* Base 50 |
0 | 1 | 22 | 115 | 328 | 511 | 663 | 600 | 372 | 147 | 23 | 0 | 2788 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/04 | 4/10 | 4/23 | 5/19 | 5/27 | 10/07 | 9/21 | 9/22 | 10/26 | 11/03 |
| 30 | 4/25 | 4/08 | 4/10 | 5/15 | 5/27 | 10/17 | 9/21 | 9/24 | 11/06 | 11/11 |
| 28 | 4/22 | 4/04 | 4/09 | 5/07 | 5/16 | 10/18 | 9/23 | 9/29 | 11/09 | 11/12 |
| 24 | 4/08 | 3/19 | 3/23 | 4/20 | 4/28 | 11/02 | 10/08 | 10/15 | 11/15 | 1/01 |
| 20 | 4/04 | 2/28 | 3/17 | 4/09 | 4/13 | 11/11 | 10/19 | 10/31 | 11/24 | 1/01 |
| 16 | 3/25 | 2/27 | 3/09 | 4/08 | 4/09 | 11/21 | 10/19 | 11/06 | 12/04 | 1/02 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 154 | 121 | 137 | 181 | 204 |
| 30 | 173 | 137 | 140 | 202 | 216 |
| 28 | 184 | 140 | 153 | 206 | 217 |
| 24 | 209 | 175 | 187 | 228 | 269 |
| 20 | 223 | 200 | 209 | 255 | 269 |
| 16 | 234 | 210 | 217 | 263 | 280 |