| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 6b: -5°F to 0°F | |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F | |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F | |
| Average First Frost Date: | Oct. 11 - Oct. 20 | |
| Average Last Frost Date: | May 1 - May 10 | |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year | |
| Ecoregion: | 59c - Southern New England Coastal Plains and Hills | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 01740 - Bolton, MA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 15 | 17 | 26 | 36 | 47 | 56 | 62 | 60 | 51 | 39 | 32 | 21 | 38 |
| Avg Max Temp (°F) | 34 | 36 | 45 | 56 | 68 | 77 | 82 | 80 | 72 | 61 | 50 | 38 | 58 |
| Avg Precip (In.) | 4.24 | 3.4 | 4.23 | 4.21 | 3.87 | 3.85 | 3.76 | 4.13 | 4.05 | 4.32 | 4.42 | 3.98 | 48.45 |