Charleston, Utah has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.2 °C (low) to 16.5 °C (high). Annual precipitation averages 410.5 Millimeters. Charleston is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.9 °C | 2.5 °C | 50.29 mm |
| February | -7.9 °C | 5.1 °C | 43.43 mm |
| March | -3.5 °C | 10.8 °C | 36.58 mm |
| April | -0.4 °C | 15 °C | 37.08 mm |
| May | 3.4 °C | 20.4 °C | 40.64 mm |
| June | 6.9 °C | 26.7 °C | 22.1 mm |
| July | 11.1 °C | 31.8 °C | 12.95 mm |
| August | 10.7 °C | 30.7 °C | 19.81 mm |
| September | 5.7 °C | 25.4 °C | 31.75 mm |
| October | 0.2 °C | 17.8 °C | 36.07 mm |
| November | -4.5 °C | 9.5 °C | 34.29 mm |
| December | -9 °C | 2.8 °C | 45.47 mm |
| Annual | 0.2 °C | 16.5 °C | 410.46 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 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 | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |