Green River, Wyoming has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -1.6 °C (low) to 15.2 °C (high). Annual precipitation averages 254.5 Millimeters. Green River is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.3 °C | 0.9 °C | 15.24 mm |
| February | -11.3 °C | 3 °C | 13.72 mm |
| March | -5.8 °C | 8.9 °C | 20.07 mm |
| April | -2.2 °C | 13.9 °C | 29.97 mm |
| May | 2.6 °C | 19.4 °C | 39.62 mm |
| June | 6.9 °C | 25.9 °C | 24.64 mm |
| July | 10.5 °C | 30.7 °C | 12.95 mm |
| August | 9.5 °C | 29.7 °C | 16 mm |
| September | 4.3 °C | 24.4 °C | 25.4 mm |
| October | -1.5 °C | 16.3 °C | 26.67 mm |
| November | -7.1 °C | 7.6 °C | 17.02 mm |
| December | -12.3 °C | 1.3 °C | 13.21 mm |
| Annual | -1.6 °C | 15.2 °C | 254.51 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| 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 | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |