Franklin, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.7 °F (low) to 58 °F (high). Annual precipitation averages 45.2 Inches. Franklin is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.5 °F | 31.2 °F | 3.0 in. |
| February | 12.8 °F | 34.4 °F | 2.81 in. |
| March | 21.6 °F | 42.9 °F | 3.33 in. |
| April | 32.6 °F | 56.8 °F | 3.47 in. |
| May | 44.1 °F | 69.3 °F | 3.67 in. |
| June | 53.7 °F | 77.8 °F | 4.18 in. |
| July | 59.7 °F | 83.2 °F | 4.39 in. |
| August | 57.4 °F | 81.5 °F | 3.74 in. |
| September | 49.8 °F | 73.7 °F | 3.6 in. |
| October | 37.9 °F | 60.3 °F | 5.07 in. |
| November | 28.5 °F | 47.6 °F | 3.82 in. |
| December | 18.8 °F | 36.7 °F | 4.1 in. |
| Annual | 35.7 °F | 58 °F | 45.18 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |