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 | 3 | 47 | 225 | 552 | 796 | 956 | 870 | 591 | 285 | 54 | 4 | 4272 |
| GDD Base 45 |
0 | 1 | 22 | 132 | 401 | 647 | 801 | 716 | 445 | 171 | 23 | 1 | 3269 |
| GDD Base 50 |
0 | 0 | 9 | 69 | 264 | 498 | 646 | 561 | 307 | 89 | 8 | 0 | 2382 |
| GDD Base 55 |
0 | 0 | 3 | 31 | 152 | 351 | 492 | 407 | 189 | 38 | 2 | 0 | 1617 |
| GDD Base 60 |
0 | 0 | 1 | 13 | 76 | 217 | 338 | 259 | 99 | 12 | 0 | 0 | 985 |
| MGDD* Base 50 |
0 | 2 | 36 | 155 | 347 | 513 | 633 | 566 | 368 | 183 | 36 | 2 | 2772 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/10 | 4/10 | 4/23 | 5/27 | 6/11 | 9/30 | 9/03 | 9/19 | 10/11 | 10/16 |
| 30 | 5/08 | 3/27 | 4/14 | 5/22 | 5/27 | 10/04 | 9/12 | 9/21 | 10/13 | 10/18 |
| 28 | 4/25 | 3/27 | 4/06 | 5/13 | 5/24 | 10/07 | 9/12 | 9/22 | 10/27 | 11/02 |
| 24 | 4/13 | 3/27 | 4/05 | 4/27 | 5/09 | 10/23 | 9/22 | 10/03 | 11/11 | 11/14 |
| 20 | 4/07 | 3/07 | 3/21 | 4/13 | 5/01 | 11/03 | 9/22 | 10/13 | 11/14 | 11/20 |
| 16 | 3/27 | 3/07 | 3/12 | 4/09 | 4/18 | 11/13 | 10/02 | 10/21 | 12/01 | 12/21 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 145 | 104 | 115 | 164 | 171 |
| 30 | 151 | 119 | 132 | 176 | 191 |
| 28 | 162 | 126 | 135 | 189 | 208 |
| 24 | 194 | 147 | 156 | 214 | 217 |
| 20 | 209 | 167 | 190 | 224 | 258 |
| 16 | 221 | 191 | 201 | 259 | 272 |