Kirby, Wyoming has a Cold Desert Climate climate (Köppen classification: BWk). Average annual temperatures range from -1.1 °C (low) to 15.8 °C (high). Annual precipitation averages 261.1 Millimeters. Kirby 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 Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -15.1 °C | 0.3 °C | 6.86 mm |
| February | -12 °C | 3.4 °C | 8.13 mm |
| March | -5.8 °C | 10.8 °C | 19.56 mm |
| April | -0.9 °C | 15.4 °C | 29.97 mm |
| May | 4.6 °C | 20.5 °C | 54.1 mm |
| June | 9.1 °C | 26.7 °C | 33.27 mm |
| July | 12.6 °C | 31.8 °C | 17.53 mm |
| August | 10.9 °C | 30.8 °C | 15.75 mm |
| September | 5.7 °C | 24.8 °C | 27.69 mm |
| October | -0.8 °C | 16.5 °C | 25.65 mm |
| November | -8.1 °C | 7.7 °C | 13.46 mm |
| December | -13.7 °C | 0.9 °C | 9.14 mm |
| Annual | -1.1 °C | 15.8 °C | 261.11 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| 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 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BWk - Cold Desert Climate |