Big Horn, Wyoming has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.2 °C (low) to 14.7 °C (high). Annual precipitation averages 495.6 Millimeters. Big Horn is located in USDA Plant Hardiness Zone 5a. 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 | -11 °C | 2.4 °C | 19.81 mm |
| February | -10.1 °C | 3.3 °C | 23.62 mm |
| March | -5.3 °C | 8.9 °C | 39.37 mm |
| April | -1 °C | 12.9 °C | 62.99 mm |
| May | 4.1 °C | 17.8 °C | 92.71 mm |
| June | 8.9 °C | 23.8 °C | 57.66 mm |
| July | 12.3 °C | 29.6 °C | 34.04 mm |
| August | 11 °C | 29 °C | 26.16 mm |
| September | 6.2 °C | 23.2 °C | 43.94 mm |
| October | -0.3 °C | 14.9 °C | 51.31 mm |
| November | -6.2 °C | 8.1 °C | 26.16 mm |
| December | -10.7 °C | 2.7 °C | 17.78 mm |
| Annual | -0.2 °C | 14.7 °C | 495.55 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 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |