| 2023 Hardiness Zone: | Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F |
| Average First Frost Date: | Oct. 1 - Oct. 10 |
| Average Last Frost Date: | May 21 - May 31 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 58b - Western New England Marble Valleys |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 01226 - Dalton, MA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 10 | 11 | 20 | 31 | 42 | 50 | 55 | 53 | 45 | 34 | 27 | 16 | 33 |
| Avg Max Temp (°F) | 30 | 32 | 41 | 54 | 66 | 74 | 79 | 77 | 69 | 58 | 46 | 35 | 55 |
| Avg Precip (In.) | 3.75 | 3.01 | 3.9 | 4.32 | 5 | 4.41 | 4.68 | 4.8 | 4.45 | 4.42 | 4.41 | 3.69 | 50.84 |