Danbury, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.8 °C (low) to 15.8 °C (high). Annual precipitation averages 1295.7 Millimeters. Danbury is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.3 °C | 2.3 °C | 99.57 mm |
| February | -6.4 °C | 3.8 °C | 76.2 mm |
| March | -2.4 °C | 8.2 °C | 104.65 mm |
| April | 3.3 °C | 15.3 °C | 100.33 mm |
| May | 8.9 °C | 21.2 °C | 96.52 mm |
| June | 14.1 °C | 25.8 °C | 117.86 mm |
| July | 17.2 °C | 28.6 °C | 115.57 mm |
| August | 16.3 °C | 27.6 °C | 119.63 mm |
| September | 12.2 °C | 23.6 °C | 121.92 mm |
| October | 5.7 °C | 17.2 °C | 121.92 mm |
| November | 0.3 °C | 10.9 °C | 106.43 mm |
| December | -4.1 °C | 4.9 °C | 115.06 mm |
| Annual | 4.8 °C | 15.8 °C | 1295.66 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |