Smithfield, Utah has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 1.2 °C (low) to 15.6 °C (high). Annual precipitation averages 480.1 Millimeters. Smithfield is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.5 °C | 0.3 °C | 49.02 mm |
| February | -7.6 °C | 2.9 °C | 40.13 mm |
| March | -2.4 °C | 9.6 °C | 50.04 mm |
| April | 0.9 °C | 14.5 °C | 57.66 mm |
| May | 4.9 °C | 19.8 °C | 63.25 mm |
| June | 8.6 °C | 26 °C | 30.48 mm |
| July | 12.6 °C | 31.6 °C | 16 mm |
| August | 11.8 °C | 30.9 °C | 19.56 mm |
| September | 6.9 °C | 25.1 °C | 33.78 mm |
| October | 1.1 °C | 16.8 °C | 44.96 mm |
| November | -3.8 °C | 8.1 °C | 34.8 mm |
| December | -8.6 °C | 1.1 °C | 40.39 mm |
| Annual | 1.2 °C | 15.6 °C | 480.07 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |