Franklin, Connecticut has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 40.7 °F (low) to 61 °F (high). Annual precipitation averages 47 Inches. Franklin is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 19.0 °F | 37.1 °F | 3.62 in. |
| February | 20.8 °F | 39.8 °F | 3.16 in. |
| March | 28.0 °F | 47.5 °F | 4.49 in. |
| April | 37.8 °F | 59.9 °F | 4.28 in. |
| May | 47.6 °F | 70.0 °F | 3.21 in. |
| June | 56.8 °F | 78.4 °F | 3.44 in. |
| July | 63.1 °F | 83.5 °F | 3.65 in. |
| August | 61.3 °F | 82.2 °F | 4.06 in. |
| September | 53.2 °F | 74.9 °F | 4.05 in. |
| October | 42.5 °F | 63.7 °F | 4.58 in. |
| November | 33.0 °F | 52.6 °F | 3.91 in. |
| December | 25.3 °F | 42.7 °F | 4.58 in. |
| Annual | 40.7 °F | 61 °F | 47.03 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |