Harrisville, Rhode Island has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 40.1 °F (low) to 59.9 °F (high). Annual precipitation averages 51.1 Inches. Harrisville 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 | 18.4 °F | 36.4 °F | 3.97 in. |
| February | 19.7 °F | 38.8 °F | 3.51 in. |
| March | 26.9 °F | 46.2 °F | 4.84 in. |
| April | 37.0 °F | 58.4 °F | 4.59 in. |
| May | 47.0 °F | 69.0 °F | 3.62 in. |
| June | 56.3 °F | 77.1 °F | 4.29 in. |
| July | 62.4 °F | 82.7 °F | 3.79 in. |
| August | 60.7 °F | 80.9 °F | 4.23 in. |
| September | 53.6 °F | 73.9 °F | 4.08 in. |
| October | 42.5 °F | 62.4 °F | 5.08 in. |
| November | 32.7 °F | 51.6 °F | 4.15 in. |
| December | 24.3 °F | 41.5 °F | 4.95 in. |
| Annual | 40.1 °F | 59.9 °F | 51.1 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 |