Hopkinton, Rhode Island has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 5.5 °C (low) to 15.6 °C (high). Annual precipitation averages 1257.1 Millimeters. Hopkinton 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 | -6.4 °C | 3.3 °C | 101.35 mm |
| February | -5.5 °C | 4.4 °C | 88.9 mm |
| March | -1.7 °C | 8.6 °C | 128.78 mm |
| April | 3.6 °C | 14.1 °C | 117.6 mm |
| May | 9.1 °C | 19.5 °C | 89.66 mm |
| June | 14.3 °C | 24.6 °C | 97.79 mm |
| July | 17.7 °C | 27.4 °C | 82.3 mm |
| August | 16.8 °C | 26.9 °C | 98.81 mm |
| September | 12.8 °C | 23.2 °C | 101.85 mm |
| October | 6.7 °C | 17.1 °C | 120.9 mm |
| November | 1.3 °C | 11.5 °C | 105.16 mm |
| December | -3.1 °C | 6.3 °C | 123.95 mm |
| Annual | 5.5 °C | 15.6 °C | 1257.05 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |