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 | 4 | 55 | 221 | 540 | 787 | 955 | 892 | 614 | 300 | 67 | 5 | 4378 |
| GDD Base 45 |
0 | 1 | 25 | 130 | 392 | 638 | 801 | 738 | 467 | 183 | 30 | 2 | 3363 |
| GDD Base 50 |
0 | 0 | 10 | 70 | 258 | 491 | 648 | 584 | 327 | 97 | 12 | 0 | 2468 |
| GDD Base 55 |
0 | 0 | 4 | 34 | 151 | 347 | 494 | 431 | 203 | 43 | 3 | 0 | 1694 |
| GDD Base 60 |
0 | 0 | 1 | 15 | 76 | 216 | 343 | 283 | 108 | 15 | 0 | 0 | 1051 |
| MGDD* Base 50 |
0 | 4 | 43 | 152 | 342 | 507 | 632 | 585 | 393 | 205 | 44 | 4 | 2871 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/17 | 4/22 | 4/29 | 6/10 | 6/25 | 9/24 | 8/16 | 9/07 | 10/09 | 10/17 |
| 30 | 5/11 | 4/22 | 4/24 | 5/30 | 6/09 | 10/02 | 9/07 | 9/19 | 10/13 | 10/17 |
| 28 | 5/03 | 4/09 | 4/17 | 5/18 | 5/27 | 10/04 | 9/20 | 9/22 | 10/17 | 10/21 |
| 24 | 4/22 | 3/27 | 4/07 | 5/05 | 5/09 | 10/18 | 9/22 | 9/30 | 11/04 | 11/16 |
| 20 | 4/10 | 3/12 | 4/01 | 4/23 | 4/29 | 10/30 | 9/23 | 10/10 | 11/12 | 11/19 |
| 16 | 4/04 | 3/11 | 3/21 | 4/12 | 4/19 | 11/08 | 10/03 | 10/20 | 11/21 | 12/08 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 135 | 52 | 105 | 156 | 168 |
| 30 | 148 | 104 | 115 | 164 | 168 |
| 28 | 153 | 125 | 135 | 179 | 190 |
| 24 | 176 | 150 | 162 | 210 | 221 |
| 20 | 200 | 166 | 181 | 215 | 248 |
| 16 | 217 | 192 | 197 | 242 | 255 |