Growing Degree Day Averages
Derived from 1971-1998 Data
| Element | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN |
| GDD Base 40 |
0 | 1 | 41 | 222 | 543 | 749 | 921 | 880 | 592 | 281 | 42 | 1 | 4128 |
| GDD Base 45 |
0 | 0 | 18 | 130 | 393 | 603 | 769 | 725 | 445 | 168 | 17 | 0 | 3151 |
| GDD Base 50 |
0 | 0 | 7 | 69 | 259 | 458 | 617 | 570 | 307 | 87 | 5 | 0 | 2289 |
| GDD Base 55 |
0 | 0 | 2 | 33 | 150 | 316 | 465 | 415 | 189 | 37 | 0 | 0 | 1546 |
| GDD Base 60 |
0 | 0 | 0 | 14 | 77 | 190 | 316 | 267 | 98 | 11 | 0 | 0 | 940 |
| MGDD* Base 50 |
0 | 3 | 36 | 178 | 375 | 493 | 607 | 577 | 387 | 196 | 32 | 1 | 2794 |
| Date of Last Spring Occurrence | Date of First Fall Occurrence | |||||||||
| Base Temp °F |
Median | Early | 90% | 10% | Late | Median | Early | 90% | 10% | Late |
| 32 | 6/01 | 5/02 | 5/11 | 6/11 | 6/21 | 9/19 | 9/01 | 9/08 | 10/02 | 10/06 |
| 30 | 5/22 | 5/02 | 5/03 | 6/10 | 6/21 | 9/23 | 9/03 | 9/10 | 10/02 | 10/06 |
| 28 | 5/13 | 4/26 | 5/02 | 5/29 | 6/11 | 10/01 | 9/03 | 9/21 | 10/09 | 10/16 |
| 24 | 4/25 | 4/04 | 4/09 | 5/10 | 5/27 | 10/08 | 9/20 | 9/27 | 10/31 | 11/02 |
| 20 | 4/18 | 4/02 | 4/05 | 4/29 | 5/03 | 10/28 | 9/23 | 10/04 | 11/06 | 11/12 |
| 16 | 4/09 | 3/20 | 3/25 | 4/23 | 4/26 | 11/02 | 10/02 | 10/13 | 11/13 | 11/15 |
| Base Temp °F |
Median | Shortest | 10% | 90% | Longest |
| 32 | 112 | 89 | 95 | 136 | 139 |
| 30 | 124 | 101 | 104 | 141 | 146 |
| 28 | 136 | 112 | 117 | 156 | 168 |
| 24 | 166 | 126 | 139 | 190 | 194 |
| 20 | 191 | 152 | 170 | 212 | 218 |
| 16 | 210 | 161 | 176 | 221 | 226 |