Grantsville, Utah has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.1 °C (low) to 17.6 °C (high). Annual precipitation averages 291.8 Millimeters. Grantsville 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 | -6.6 °C | 3.3 °C | 22.86 mm |
| February | -4.4 °C | 6.4 °C | 22.35 mm |
| March | -0.4 °C | 12.1 °C | 28.7 mm |
| April | 2.6 °C | 15.7 °C | 37.08 mm |
| May | 7.1 °C | 21.6 °C | 39.37 mm |
| June | 11.7 °C | 28 °C | 18.8 mm |
| July | 17.2 °C | 33.8 °C | 12.95 mm |
| August | 16.3 °C | 32.7 °C | 16.26 mm |
| September | 10.5 °C | 26.5 °C | 21.84 mm |
| October | 3.7 °C | 17.9 °C | 26.67 mm |
| November | -2 °C | 9.7 °C | 23.62 mm |
| December | -6.2 °C | 3.3 °C | 21.34 mm |
| Annual | 4.1 °C | 17.6 °C | 291.84 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 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 | Extreme Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |