Big Sky, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -5 °C (low) to 9.8 °C (high). Annual precipitation averages 731.8 Millimeters. Big Sky is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Aug. 21 - Aug. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.3 °C | -2.1 °C | 56.39 mm |
| February | -13.3 °C | -0.4 °C | 49.78 mm |
| March | -9.9 °C | 3.8 °C | 52.83 mm |
| April | -6.1 °C | 8.1 °C | 62.99 mm |
| May | -1.4 °C | 13.2 °C | 93.22 mm |
| June | 1.8 °C | 18.1 °C | 92.96 mm |
| July | 4.9 °C | 24.1 °C | 49.02 mm |
| August | 4.1 °C | 23.9 °C | 49.53 mm |
| September | 0.8 °C | 18.6 °C | 47.75 mm |
| October | -4.1 °C | 10.6 °C | 60.45 mm |
| November | -9.7 °C | 1.9 °C | 52.83 mm |
| December | -13.8 °C | -2.8 °C | 64.01 mm |
| Annual | -5 °C | 9.8 °C | 731.76 mm |
| Average First Frost Date | Aug. 21 - Aug. 31 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 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 | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |