Norwich, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.9 °C (low) to 14.3 °C (high). Annual precipitation averages 1111.3 Millimeters. Norwich 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 | -10.6 °C | 0 °C | 77.98 mm |
| February | -10.2 °C | 1.6 °C | 66.8 mm |
| March | -6.2 °C | 6.1 °C | 84.84 mm |
| April | 0.3 °C | 13.8 °C | 91.95 mm |
| May | 6.4 °C | 20.8 °C | 94.23 mm |
| June | 11.4 °C | 25.3 °C | 123.19 mm |
| July | 13.9 °C | 27.5 °C | 104.9 mm |
| August | 13.2 °C | 26.7 °C | 111 mm |
| September | 9.3 °C | 22.9 °C | 100.84 mm |
| October | 3.6 °C | 15.9 °C | 93.47 mm |
| November | -1.7 °C | 8.8 °C | 77.72 mm |
| December | -6.1 °C | 2.7 °C | 84.33 mm |
| Annual | 1.9 °C | 14.3 °C | 1111.25 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 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |