| 2023 Hardiness Zone: | 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 06237 - Columbia, CT | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 14 | 16 | 26 | 35 | 45 | 54 | 59 | 57 | 49 | 37 | 30 | 21 | 37 |
| Avg Max Temp (°F) | 35 | 37 | 46 | 57 | 69 | 77 | 81 | 80 | 72 | 62 | 51 | 40 | 59 |
| Avg Precip (In.) | 4.46 | 3.38 | 4.39 | 4.37 | 4.07 | 3.94 | 4.23 | 4.26 | 4.28 | 4.51 | 4.54 | 4.18 | 50.6 |