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 |
2 | 7 | 59 | 192 | 494 | 785 | 988 | 944 | 686 | 357 | 86 | 11 | 4617 |
| GDD Base 45 |
0 | 2 | 30 | 106 | 347 | 635 | 833 | 789 | 536 | 225 | 39 | 3 | 3551 |
| GDD Base 50 |
0 | 0 | 14 | 53 | 220 | 485 | 678 | 634 | 390 | 123 | 15 | 0 | 2616 |
| GDD Base 55 |
0 | 0 | 5 | 25 | 125 | 342 | 523 | 479 | 253 | 56 | 4 | 0 | 1817 |
| GDD Base 60 |
0 | 0 | 1 | 11 | 64 | 216 | 369 | 326 | 142 | 20 | 0 | 0 | 1155 |
| MGDD* Base 50 |
0 | 3 | 33 | 104 | 271 | 487 | 662 | 626 | 406 | 177 | 38 | 4 | 2817 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 4/26 | 4/03 | 4/10 | 5/12 | 5/16 | 10/18 | 9/22 | 10/05 | 11/04 | 11/19 |
| 30 | 4/20 | 4/01 | 4/06 | 5/06 | 5/09 | 10/28 | 9/23 | 10/13 | 11/12 | 11/19 |
| 28 | 4/13 | 3/26 | 4/03 | 4/23 | 4/29 | 11/02 | 9/23 | 10/20 | 11/12 | 11/22 |
| 24 | 4/06 | 3/16 | 3/19 | 4/13 | 4/29 | 11/11 | 10/20 | 10/28 | 11/25 | 12/07 |
| 20 | 3/20 | 2/21 | 3/14 | 4/09 | 4/11 | 11/20 | 10/24 | 11/04 | 12/07 | 12/15 |
| 16 | 3/15 | 2/17 | 2/20 | 3/27 | 4/07 | 11/30 | 11/03 | 11/10 | 12/17 | 12/24 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 173 | 135 | 162 | 201 | 223 |
| 30 | 188 | 139 | 175 | 213 | 226 |
| 28 | 198 | 166 | 183 | 220 | 229 |
| 24 | 219 | 193 | 203 | 243 | 248 |
| 20 | 238 | 209 | 217 | 270 | 278 |
| 16 | 263 | 219 | 236 | 285 | 300 |