Grantsville, Utah has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.4 °F (low) to 63.7 °F (high). Annual precipitation averages 11.5 Inches. 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 | 20.1 °F | 37.9 °F | 0.9 in. |
| February | 24.0 °F | 43.6 °F | 0.88 in. |
| March | 31.3 °F | 53.8 °F | 1.13 in. |
| April | 36.7 °F | 60.3 °F | 1.46 in. |
| May | 44.7 °F | 70.9 °F | 1.55 in. |
| June | 53.1 °F | 82.4 °F | 0.74 in. |
| July | 63.0 °F | 92.8 °F | 0.51 in. |
| August | 61.3 °F | 90.8 °F | 0.64 in. |
| September | 50.9 °F | 79.7 °F | 0.86 in. |
| October | 38.6 °F | 64.3 °F | 1.05 in. |
| November | 28.4 °F | 49.4 °F | 0.93 in. |
| December | 20.8 °F | 38.0 °F | 0.84 in. |
| Annual | 39.4 °F | 63.7 °F | 11.49 in. |
| 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 : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |