Smithfield, Utah has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 34.2 °F (low) to 60 °F (high). Annual precipitation averages 18.9 Inches. 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 | 14.9 °F | 32.6 °F | 1.93 in. |
| February | 18.3 °F | 37.3 °F | 1.58 in. |
| March | 27.6 °F | 49.2 °F | 1.97 in. |
| April | 33.6 °F | 58.1 °F | 2.27 in. |
| May | 40.9 °F | 67.7 °F | 2.49 in. |
| June | 47.4 °F | 78.8 °F | 1.2 in. |
| July | 54.7 °F | 88.9 °F | 0.63 in. |
| August | 53.3 °F | 87.6 °F | 0.77 in. |
| September | 44.4 °F | 77.1 °F | 1.33 in. |
| October | 33.9 °F | 62.3 °F | 1.77 in. |
| November | 25.2 °F | 46.6 °F | 1.37 in. |
| December | 16.5 °F | 34.0 °F | 1.59 in. |
| Annual | 34.2 °F | 60 °F | 18.9 in. |
| 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 : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |