Watch Hill, Rhode Island has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 7.4 °C (low) to 14.9 °C (high). Annual precipitation averages 1192.5 Millimeters. Watch Hill is located in USDA Plant Hardiness Zone 7a. 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 | -3.8 °C | 3.8 °C | 98.55 mm |
| February | -3.3 °C | 4.3 °C | 85.34 mm |
| March | -0.2 °C | 7.6 °C | 124.21 mm |
| April | 4.7 °C | 12.8 °C | 112.78 mm |
| May | 9.7 °C | 17.4 °C | 86.61 mm |
| June | 15 °C | 22.5 °C | 93.98 mm |
| July | 18.7 °C | 25.9 °C | 75.44 mm |
| August | 18.6 °C | 25.4 °C | 91.69 mm |
| September | 15.4 °C | 22.6 °C | 88.9 mm |
| October | 9.8 °C | 17.1 °C | 116.59 mm |
| November | 4.6 °C | 11.9 °C | 99.82 mm |
| December | -0.2 °C | 7.1 °C | 118.62 mm |
| Annual | 7.4 °C | 14.9 °C | 1192.53 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 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |