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 | 36 | 201 | 528 | 780 | 939 | 875 | 583 | 271 | 46 | 2 | 4252 |
| GDD Base 45 |
0 | 0 | 16 | 116 | 381 | 630 | 784 | 720 | 437 | 161 | 19 | 0 | 3256 |
| GDD Base 50 |
0 | 0 | 6 | 61 | 249 | 481 | 629 | 565 | 298 | 82 | 7 | 0 | 2371 |
| GDD Base 55 |
0 | 0 | 2 | 28 | 145 | 336 | 475 | 410 | 181 | 35 | 1 | 0 | 1610 |
| GDD Base 60 |
0 | 0 | 0 | 12 | 73 | 207 | 322 | 262 | 95 | 11 | 0 | 0 | 981 |
| MGDD* Base 50 |
0 | 1 | 24 | 127 | 319 | 494 | 621 | 567 | 348 | 152 | 25 | 1 | 2674 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 5/06 | 4/17 | 4/24 | 5/18 | 5/27 | 10/01 | 9/20 | 9/22 | 10/11 | 10/14 |
| 30 | 5/03 | 4/07 | 4/23 | 5/11 | 5/16 | 10/04 | 9/20 | 9/23 | 10/15 | 10/22 |
| 28 | 4/23 | 3/25 | 4/09 | 5/08 | 5/11 | 10/09 | 9/22 | 9/27 | 10/27 | 11/10 |
| 24 | 4/12 | 3/24 | 4/03 | 4/24 | 5/06 | 10/31 | 10/02 | 10/10 | 11/13 | 11/16 |
| 20 | 4/07 | 3/14 | 3/20 | 4/13 | 4/18 | 11/05 | 10/10 | 10/20 | 11/16 | 11/29 |
| 16 | 3/27 | 2/27 | 3/14 | 4/10 | 4/16 | 11/12 | 10/20 | 11/01 | 11/28 | 12/21 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 148 | 119 | 133 | 160 | 167 |
| 30 | 157 | 137 | 140 | 169 | 178 |
| 28 | 171 | 138 | 148 | 194 | 199 |
| 24 | 202 | 151 | 175 | 217 | 234 |
| 20 | 216 | 190 | 196 | 235 | 260 |
| 16 | 229 | 193 | 210 | 251 | 280 |