Columbia Falls, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.3 °C (low) to 12.7 °C (high). Annual precipitation averages 541.3 Millimeters. Columbia Falls is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.4 °C | -0.4 °C | 45.47 mm |
| February | -7.9 °C | 2.1 °C | 32.77 mm |
| March | -4.6 °C | 6.8 °C | 36.07 mm |
| April | -1 °C | 12.2 °C | 46.23 mm |
| May | 3.3 °C | 18 °C | 57.66 mm |
| June | 6.8 °C | 21.4 °C | 87.88 mm |
| July | 8.9 °C | 27.4 °C | 33.27 mm |
| August | 7.9 °C | 27.4 °C | 24.64 mm |
| September | 3.8 °C | 21.2 °C | 34.54 mm |
| October | -0.9 °C | 12.5 °C | 47.24 mm |
| November | -4.2 °C | 4.3 °C | 43.94 mm |
| December | -7.6 °C | -0.5 °C | 51.56 mm |
| Annual | -0.3 °C | 12.7 °C | 541.27 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |