| 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 6a: -10F to -5F |
| Average First Frost Date: | Oct. 1 - Oct. 10 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 59c - Southern New England Coastal Plains and Hills |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 06795 - Watertown, CT | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 14 | 15 | 25 | 34 | 44 | 54 | 59 | 57 | 49 | 37 | 29 | 20 | 36 |
| Avg Max Temp (°F) | 34 | 37 | 46 | 58 | 70 | 78 | 83 | 81 | 73 | 62 | 50 | 39 | 59 |
| Avg Precip (In.) | 4.12 | 3.18 | 4.57 | 4.32 | 4.57 | 4.26 | 4.33 | 4.54 | 4.66 | 4.48 | 4.4 | 4.12 | 51.55 |