Jamestown, Rhode Island has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.7 °C (low) to 15 °C (high). Annual precipitation averages 1212.3 Millimeters. Jamestown is located in USDA Plant Hardiness Zone 7a. 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 | -4.8 °C | 3.6 °C | 100.33 mm |
| February | -4.1 °C | 4.5 °C | 89.66 mm |
| March | -0.7 °C | 7.6 °C | 130.3 mm |
| April | 4.4 °C | 12.7 °C | 115.06 mm |
| May | 9.7 °C | 17.9 °C | 88.65 mm |
| June | 14.9 °C | 22.8 °C | 90.68 mm |
| July | 18.3 °C | 26.3 °C | 77.47 mm |
| August | 17.8 °C | 26.1 °C | 87.88 mm |
| September | 14.4 °C | 22.8 °C | 94.49 mm |
| October | 8.6 °C | 17.1 °C | 114.3 mm |
| November | 3.4 °C | 11.7 °C | 102.62 mm |
| December | -1.4 °C | 6.8 °C | 120.9 mm |
| Annual | 6.7 °C | 15 °C | 1212.34 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 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |