Thompson, Connecticut has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.8 °F (low) to 59.1 °F (high). Annual precipitation averages 50.4 Inches. Thompson 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 | 17.0 °F | 35.3 °F | 3.96 in. |
| February | 18.1 °F | 37.8 °F | 3.43 in. |
| March | 25.5 °F | 45.4 °F | 4.51 in. |
| April | 35.6 °F | 57.9 °F | 4.5 in. |
| May | 45.9 °F | 68.6 °F | 3.52 in. |
| June | 55.0 °F | 76.6 °F | 4.37 in. |
| July | 61.1 °F | 81.8 °F | 3.95 in. |
| August | 59.3 °F | 80.0 °F | 4.31 in. |
| September | 52.2 °F | 73.2 °F | 4.2 in. |
| October | 40.8 °F | 61.5 °F | 4.9 in. |
| November | 31.4 °F | 50.8 °F | 4.02 in. |
| December | 23.1 °F | 40.5 °F | 4.73 in. |
| Annual | 38.8 °F | 59.1 °F | 50.4 in. |
| 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 : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |