Brookfield, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.5 °C (low) to 15.8 °C (high). Annual precipitation averages 1292.1 Millimeters. Brookfield 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 | -7.6 °C | 2.2 °C | 96.01 mm |
| February | -6.7 °C | 3.8 °C | 75.69 mm |
| March | -2.7 °C | 8.3 °C | 104.14 mm |
| April | 3.1 °C | 15.3 °C | 100.08 mm |
| May | 8.7 °C | 21.3 °C | 97.28 mm |
| June | 13.8 °C | 25.9 °C | 118.36 mm |
| July | 16.8 °C | 28.7 °C | 120.4 mm |
| August | 16 °C | 27.6 °C | 121.41 mm |
| September | 11.8 °C | 23.6 °C | 120.4 mm |
| October | 5.4 °C | 17.1 °C | 122.68 mm |
| November | 0 °C | 10.8 °C | 103.89 mm |
| December | -4.3 °C | 4.8 °C | 111.76 mm |
| Annual | 4.5 °C | 15.8 °C | 1292.1 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 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |