Powder River, Wyoming has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -0.3 °C (low) to 14.8 °C (high). Annual precipitation averages 287.5 Millimeters. Powder River 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. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.1 °C | 1.4 °C | 9.91 mm |
| February | -9.8 °C | 2.6 °C | 10.16 mm |
| March | -5.3 °C | 8.3 °C | 26.16 mm |
| April | -1.7 °C | 12.7 °C | 32 mm |
| May | 3.2 °C | 18.4 °C | 61.47 mm |
| June | 7.9 °C | 25.3 °C | 34.04 mm |
| July | 12.1 °C | 30.9 °C | 23.88 mm |
| August | 10.9 °C | 29.9 °C | 13.46 mm |
| September | 5.8 °C | 23.7 °C | 25.65 mm |
| October | -0.2 °C | 15.2 °C | 25.15 mm |
| November | -5.9 °C | 7.4 °C | 12.7 mm |
| December | -10.1 °C | 1.6 °C | 12.95 mm |
| Annual | -0.3 °C | 14.8 °C | 287.53 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| 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 | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |