Norwalk, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 44.5 °F (low) to 61.6 °F (high). Annual precipitation averages 49.1 Inches. Norwalk is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 23.2 °F | 38.9 °F | 3.97 in. |
| February | 24.4 °F | 40.7 °F | 2.91 in. |
| March | 31.1 °F | 47.8 °F | 4.12 in. |
| April | 41.1 °F | 59.4 °F | 3.92 in. |
| May | 50.6 °F | 69.4 °F | 3.71 in. |
| June | 60.2 °F | 78.3 °F | 4.99 in. |
| July | 66.1 °F | 83.7 °F | 3.68 in. |
| August | 65.1 °F | 82.2 °F | 4.18 in. |
| September | 58.0 °F | 76.1 °F | 4.71 in. |
| October | 47.1 °F | 64.6 °F | 4.35 in. |
| November | 37.4 °F | 53.8 °F | 4.0 in. |
| December | 29.5 °F | 44.2 °F | 4.57 in. |
| Annual | 44.5 °F | 61.6 °F | 49.11 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |