Greybull, Wyoming has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -0.5 °C (low) to 15.7 °C (high). Annual precipitation averages 172.5 Millimeters. Greybull is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -15.2 °C | -1.4 °C | 6.1 mm |
| February | -11.9 °C | 2.4 °C | 6.86 mm |
| March | -5.3 °C | 10.4 °C | 6.86 mm |
| April | -0.1 °C | 15.9 °C | 16.76 mm |
| May | 5.7 °C | 21.3 °C | 32.51 mm |
| June | 10.4 °C | 27.3 °C | 29.21 mm |
| July | 13.8 °C | 32.7 °C | 11.68 mm |
| August | 11.9 °C | 31.6 °C | 7.62 mm |
| September | 6.4 °C | 25.2 °C | 21.59 mm |
| October | -0.2 °C | 16.4 °C | 17.78 mm |
| November | -7.4 °C | 7.1 °C | 9.4 mm |
| December | -13.7 °C | -0.2 °C | 6.1 mm |
| Annual | -0.5 °C | 15.7 °C | 172.47 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |