| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°F | |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F 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 11 - May 20 | |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year | |
| Ecoregion: | 58g - Worcester/Monadnock Plateau | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 01430 - Ashburnham, MA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 10 | 12 | 22 | 32 | 42 | 51 | 56 | 54 | 46 | 35 | 27 | 16 | 34 |
| Avg Max Temp (°F) | 31 | 33 | 42 | 55 | 67 | 75 | 80 | 78 | 70 | 59 | 46 | 35 | 56 |
| Avg Precip (In.) | 4.13 | 3.22 | 4.24 | 4.17 | 3.99 | 4.03 | 4.01 | 4.25 | 3.84 | 4.16 | 4.29 | 3.98 | 48.31 |