Tolland, Connecticut has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.6 °C (low) to 14.7 °C (high). Annual precipitation averages 1248.7 Millimeters. Tolland 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.3 °C | 1.4 °C | 87.63 mm |
| February | -7.9 °C | 2.8 °C | 77.98 mm |
| March | -3.7 °C | 7.1 °C | 106.93 mm |
| April | 1.9 °C | 13.8 °C | 105.92 mm |
| May | 7.3 °C | 19.7 °C | 91.69 mm |
| June | 12.6 °C | 24.3 °C | 112.52 mm |
| July | 15.7 °C | 27.2 °C | 102.36 mm |
| August | 14.7 °C | 26.3 °C | 114.3 mm |
| September | 10.8 °C | 22.6 °C | 116.33 mm |
| October | 4.6 °C | 16.1 °C | 125.48 mm |
| November | -0.4 °C | 10.1 °C | 95.76 mm |
| December | -4.7 °C | 4.6 °C | 111.76 mm |
| Annual | 3.6 °C | 14.7 °C | 1248.66 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |