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 |
3 | 7 | 52 | 161 | 438 | 720 | 943 | 923 | 670 | 355 | 90 | 11 | 4336 |
| GDD Base 45 |
0 | 2 | 25 | 80 | 292 | 572 | 788 | 768 | 521 | 222 | 40 | 3 | 3284 |
| GDD Base 50 |
0 | 0 | 11 | 34 | 172 | 425 | 634 | 613 | 375 | 119 | 15 | 0 | 2376 |
| GDD Base 55 |
0 | 0 | 4 | 13 | 91 | 286 | 480 | 458 | 238 | 51 | 4 | 0 | 1610 |
| GDD Base 60 |
0 | 0 | 1 | 5 | 41 | 167 | 327 | 305 | 127 | 17 | 0 | 0 | 983 |
| MGDD* Base 50 |
1 | 4 | 31 | 78 | 218 | 429 | 621 | 608 | 394 | 175 | 41 | 5 | 2585 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 4/25 | 4/05 | 4/10 | 5/14 | 5/30 | 10/17 | 9/21 | 9/29 | 11/06 | 11/19 |
| 30 | 4/21 | 3/27 | 4/06 | 5/08 | 5/09 | 10/24 | 9/30 | 10/09 | 11/13 | 11/19 |
| 28 | 4/13 | 3/22 | 3/29 | 5/04 | 5/09 | 11/02 | 10/17 | 10/21 | 11/16 | 11/19 |
| 24 | 4/05 | 3/12 | 3/21 | 4/10 | 4/19 | 11/07 | 10/17 | 10/21 | 11/21 | 12/14 |
| 20 | 3/21 | 2/15 | 3/04 | 4/09 | 4/18 | 11/14 | 10/24 | 11/03 | 12/10 | 12/22 |
| 16 | 3/16 | 2/09 | 2/17 | 4/06 | 4/10 | 11/23 | 11/02 | 11/11 | 12/15 | 12/23 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 172 | 129 | 151 | 205 | 226 |
| 30 | 184 | 157 | 163 | 212 | 226 |
| 28 | 203 | 166 | 178 | 221 | 230 |
| 24 | 215 | 193 | 200 | 242 | 274 |
| 20 | 235 | 206 | 216 | 275 | 285 |
| 16 | 255 | 219 | 223 | 285 | 308 |