Jaffrey, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2 °C (low) to 13.5 °C (high). Annual precipitation averages 1252 Millimeters. Jaffrey is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.8 °C | -0.6 °C | 92.2 mm |
| February | -10 °C | 1.1 °C | 84.07 mm |
| March | -5.8 °C | 5.4 °C | 103.89 mm |
| April | 0.5 °C | 12.8 °C | 99.57 mm |
| May | 6.4 °C | 19.2 °C | 100.33 mm |
| June | 11.6 °C | 24 °C | 114.55 mm |
| July | 14.6 °C | 26.8 °C | 109.98 mm |
| August | 13.7 °C | 25.9 °C | 102.62 mm |
| September | 9.5 °C | 21.8 °C | 101.09 mm |
| October | 3.4 °C | 14.7 °C | 133.6 mm |
| November | -1.8 °C | 8.3 °C | 98.81 mm |
| December | -7 °C | 2.4 °C | 111.25 mm |
| Annual | 2 °C | 13.5 °C | 1251.96 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |