Chichester, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.2 °C (low) to 13.9 °C (high). Annual precipitation averages 1148.3 Millimeters. Chichester 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 | -11.1 °C | -0.7 °C | 74.17 mm |
| February | -10.3 °C | 1.1 °C | 79.25 mm |
| March | -5.5 °C | 5.7 °C | 93.73 mm |
| April | 0.7 °C | 13.2 °C | 95.76 mm |
| May | 6.8 °C | 19.8 °C | 94.23 mm |
| June | 12.2 °C | 24.6 °C | 106.93 mm |
| July | 15.2 °C | 27.6 °C | 102.62 mm |
| August | 14.2 °C | 26.8 °C | 88.9 mm |
| September | 9.9 °C | 22.6 °C | 101.35 mm |
| October | 3.5 °C | 15.3 °C | 120.14 mm |
| November | -1.7 °C | 8.6 °C | 87.88 mm |
| December | -7 °C | 2.5 °C | 103.38 mm |
| Annual | 2.2 °C | 13.9 °C | 1148.34 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 |