Big Horn, Wyoming has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.7 °F (low) to 58.5 °F (high). Annual precipitation averages 19.5 Inches. 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 | 12.2 °F | 36.4 °F | 0.78 in. |
| February | 13.9 °F | 38.0 °F | 0.93 in. |
| March | 22.4 °F | 48.1 °F | 1.55 in. |
| April | 30.2 °F | 55.3 °F | 2.48 in. |
| May | 39.4 °F | 64.1 °F | 3.65 in. |
| June | 48.1 °F | 74.9 °F | 2.27 in. |
| July | 54.2 °F | 85.2 °F | 1.34 in. |
| August | 51.8 °F | 84.2 °F | 1.03 in. |
| September | 43.1 °F | 73.7 °F | 1.73 in. |
| October | 31.5 °F | 58.8 °F | 2.02 in. |
| November | 20.8 °F | 46.6 °F | 1.03 in. |
| December | 12.7 °F | 36.8 °F | 0.7 in. |
| Annual | 31.7 °F | 58.5 °F | 19.51 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |