| 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 Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F |
| Average First Frost Date: | Oct. 21 - Oct. 31 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 82f - Midcoast |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 04858 - South Thomaston, ME | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 13 | 14 | 25 | 33 | 43 | 52 | 57 | 57 | 50 | 40 | 31 | 20 | 36 |
| Avg Max Temp (°F) | 32 | 34 | 41 | 53 | 62 | 73 | 77 | 77 | 69 | 59 | 47 | 37 | 55 |
| Avg Precip (In.) | 4.6 | 3.9 | 4.56 | 4.12 | 3.87 | 3.59 | 3.46 | 2.71 | 4.18 | 4.02 | 5.11 | 4.3 | 48.42 |