Monroe, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.7 °C (low) to 15.5 °C (high). Annual precipitation averages 1319.8 Millimeters. Monroe 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.4 °C | 2.2 °C | 102.36 mm |
| February | -6.7 °C | 3.6 °C | 83.31 mm |
| March | -2.6 °C | 7.9 °C | 117.86 mm |
| April | 3.2 °C | 14.7 °C | 109.22 mm |
| May | 8.7 °C | 20.7 °C | 104.65 mm |
| June | 13.9 °C | 25.3 °C | 120.14 mm |
| July | 16.9 °C | 28.2 °C | 105.92 mm |
| August | 16.1 °C | 27.2 °C | 111.51 mm |
| September | 12.2 °C | 23.3 °C | 116.59 mm |
| October | 5.6 °C | 16.9 °C | 125.73 mm |
| November | 0.3 °C | 10.8 °C | 109.22 mm |
| December | -4.2 °C | 4.9 °C | 113.28 mm |
| Annual | 4.7 °C | 15.5 °C | 1319.79 mm |
| 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |