Boulder Flats, Wyoming has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.3 °C (low) to 14.7 °C (high). Annual precipitation averages 333.8 Millimeters. Boulder Flats 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 | -13.4 °C | 0.9 °C | 12.19 mm |
| February | -11.7 °C | 3.1 °C | 16.51 mm |
| March | -6 °C | 9.2 °C | 27.18 mm |
| April | -1.9 °C | 13.7 °C | 50.04 mm |
| May | 3.2 °C | 18.6 °C | 71.12 mm |
| June | 7.5 °C | 25 °C | 30.73 mm |
| July | 11.3 °C | 30.2 °C | 17.78 mm |
| August | 10.3 °C | 29.3 °C | 17.02 mm |
| September | 5.6 °C | 23.5 °C | 29.46 mm |
| October | -0.8 °C | 15.4 °C | 32.77 mm |
| November | -7.4 °C | 7 °C | 17.53 mm |
| December | -12.7 °C | 1 °C | 11.43 mm |
| Annual | -1.3 °C | 14.7 °C | 333.76 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 | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |