Roy, Utah has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40 °F (low) to 62 °F (high). Annual precipitation averages 19.3 Inches. Roy 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 20.8 °F | 36.5 °F | 2.03 in. |
| February | 24.5 °F | 41.8 °F | 1.72 in. |
| March | 32.0 °F | 52.3 °F | 1.91 in. |
| April | 37.8 °F | 59.3 °F | 2.36 in. |
| May | 45.9 °F | 69.3 °F | 2.42 in. |
| June | 53.8 °F | 80.3 °F | 1.25 in. |
| July | 62.5 °F | 90.1 °F | 0.51 in. |
| August | 60.8 °F | 88.3 °F | 0.76 in. |
| September | 51.2 °F | 77.6 °F | 1.34 in. |
| October | 39.6 °F | 62.9 °F | 1.8 in. |
| November | 29.7 °F | 48.5 °F | 1.5 in. |
| December | 21.6 °F | 36.9 °F | 1.68 in. |
| Annual | 40 °F | 62 °F | 19.28 in. |
| 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 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |