Afton, Wyoming has a Subarctic With Cool Summers And Year Around Rainfall climate (Köppen classification: Dfc). Average annual temperatures range from -3.9 °C (low) to 11.8 °C (high). Annual precipitation averages 458.5 Millimeters. Afton is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around Jun. 11 - Jun. 20 through the first frost around Aug. 1 - Aug. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.4 °C | -2.1 °C | 37.08 mm |
| February | -13.2 °C | 0.1 °C | 33.27 mm |
| March | -8.6 °C | 5.2 °C | 39.88 mm |
| April | -3.8 °C | 9.8 °C | 46.48 mm |
| May | 0.6 °C | 15.8 °C | 62.99 mm |
| June | 3.4 °C | 21.3 °C | 39.37 mm |
| July | 6.5 °C | 26.9 °C | 26.42 mm |
| August | 5.8 °C | 26.6 °C | 26.92 mm |
| September | 1.4 °C | 21.3 °C | 33.02 mm |
| October | -2.9 °C | 13.2 °C | 40.64 mm |
| November | -8.1 °C | 4.8 °C | 35.05 mm |
| December | -13.6 °C | -1.8 °C | 37.34 mm |
| Annual | -3.9 °C | 11.8 °C | 458.46 mm |
| Average First Frost Date | Aug. 1 - Aug. 10 |
| Average Last Frost Date | Jun. 11 - Jun. 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfc - Subarctic With Cool Summers And Year Around Rainfall |