Smithfield, Rhode Island has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.8 °C (low) to 15.5 °C (high). Annual precipitation averages 1314.7 Millimeters. Smithfield 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.2 °C | 2.6 °C | 98.3 mm |
| February | -6.5 °C | 3.8 °C | 88.39 mm |
| March | -2.6 °C | 7.9 °C | 125.48 mm |
| April | 3.1 °C | 14.6 °C | 118.36 mm |
| May | 8.6 °C | 20.4 °C | 93.47 mm |
| June | 13.7 °C | 25 °C | 109.47 mm |
| July | 17.2 °C | 28.1 °C | 97.03 mm |
| August | 16.3 °C | 27.3 °C | 107.95 mm |
| September | 12.3 °C | 23.3 °C | 102.62 mm |
| October | 6.1 °C | 17 °C | 134.62 mm |
| November | 0.7 °C | 11 °C | 109.98 mm |
| December | -3.9 °C | 5.4 °C | 129.03 mm |
| Annual | 4.8 °C | 15.5 °C | 1314.7 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| 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 | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |