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 | 11 | 67 | 247 | 585 | 846 | 1058 | 986 | 724 | 396 | 109 | 11 | 5041 |
| GDD Base 45 |
0 | 3 | 33 | 146 | 434 | 696 | 903 | 831 | 575 | 258 | 54 | 4 | 3939 |
| GDD Base 50 |
0 | 0 | 14 | 78 | 294 | 547 | 748 | 676 | 427 | 146 | 23 | 0 | 2957 |
| GDD Base 55 |
0 | 0 | 5 | 39 | 179 | 399 | 593 | 521 | 287 | 69 | 7 | 0 | 2104 |
| GDD Base 60 |
0 | 0 | 1 | 19 | 99 | 263 | 439 | 367 | 170 | 27 | 1 | 0 | 1388 |
| MGDD* Base 50 |
1 | 5 | 35 | 131 | 330 | 541 | 722 | 665 | 437 | 196 | 47 | 4 | 3116 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 4/20 | 4/02 | 4/06 | 4/29 | 5/01 | 10/24 | 10/02 | 10/09 | 11/10 | 11/19 |
| 30 | 4/10 | 3/27 | 4/02 | 4/27 | 5/01 | 11/02 | 10/08 | 10/14 | 11/14 | 11/19 |
| 28 | 4/10 | 3/19 | 3/26 | 4/21 | 5/01 | 11/05 | 10/09 | 10/20 | 11/14 | 11/19 |
| 24 | 4/03 | 3/14 | 3/18 | 4/11 | 4/17 | 11/12 | 10/20 | 10/27 | 11/26 | 11/29 |
| 20 | 3/21 | 2/22 | 2/25 | 4/07 | 4/09 | 11/22 | 11/06 | 11/08 | 12/07 | 12/16 |
| 16 | 3/13 | 2/09 | 2/15 | 4/01 | 4/06 | 12/01 | 11/09 | 11/14 | 12/16 | 12/25 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 187 | 167 | 171 | 211 | 223 |
| 30 | 197 | 174 | 180 | 215 | 224 |
| 28 | 213 | 178 | 192 | 222 | 224 |
| 24 | 221 | 194 | 208 | 248 | 258 |
| 20 | 249 | 218 | 219 | 272 | 278 |
| 16 | 265 | 235 | 237 | 289 | 305 |