Norwich, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1 °C (low) to 13.4 °C (high). Annual precipitation averages 1021.6 Millimeters. Norwich is located in USDA Plant Hardiness Zone 5a. 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 | -13.2 °C | -1.8 °C | 69.34 mm |
| February | -12.4 °C | 0.1 °C | 60.71 mm |
| March | -7.3 °C | 4.9 °C | 77.22 mm |
| April | -0.5 °C | 12.9 °C | 81.53 mm |
| May | 6.1 °C | 20.2 °C | 84.07 mm |
| June | 11.2 °C | 24.7 °C | 96.01 mm |
| July | 14.2 °C | 27.5 °C | 109.22 mm |
| August | 13.2 °C | 26.6 °C | 87.38 mm |
| September | 9 °C | 22.5 °C | 88.14 mm |
| October | 2.6 °C | 14.8 °C | 105.41 mm |
| November | -2.7 °C | 7.7 °C | 76.96 mm |
| December | -8.3 °C | 1.2 °C | 85.6 mm |
| Annual | 1 °C | 13.4 °C | 1021.59 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 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |