Brooklyn, Connecticut has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.4 °C (low) to 15.9 °C (high). Annual precipitation averages 1261.6 Millimeters. Brooklyn is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.7 °C | 2.8 °C | 96.01 mm |
| February | -6.8 °C | 4.2 °C | 86.87 mm |
| March | -2.7 °C | 8.4 °C | 115.57 mm |
| April | 2.7 °C | 15.4 °C | 114.55 mm |
| May | 8.3 °C | 21.1 °C | 89.66 mm |
| June | 13.3 °C | 25.4 °C | 106.43 mm |
| July | 16.8 °C | 28.3 °C | 94.74 mm |
| August | 15.7 °C | 27.4 °C | 112.78 mm |
| September | 11.6 °C | 23.7 °C | 106.43 mm |
| October | 5.6 °C | 17.3 °C | 122.94 mm |
| November | 0.2 °C | 11.3 °C | 99.31 mm |
| December | -4.3 °C | 5.7 °C | 116.33 mm |
| Annual | 4.4 °C | 15.9 °C | 1261.62 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |