Culbertson, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -1.4 °C (low) to 13.4 °C (high). Annual precipitation averages 373.4 Millimeters. Culbertson is located in USDA Plant Hardiness Zone 3b. 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 | -16.7 °C | -4.8 °C | 9.14 mm |
| February | -14.3 °C | -1.7 °C | 7.37 mm |
| March | -7.9 °C | 5.3 °C | 13.72 mm |
| April | -1.3 °C | 14.1 °C | 23.62 mm |
| May | 4.6 °C | 20.8 °C | 56.39 mm |
| June | 10.2 °C | 25.6 °C | 75.44 mm |
| July | 13.2 °C | 30 °C | 69.6 mm |
| August | 11.9 °C | 29.9 °C | 37.85 mm |
| September | 6.3 °C | 24.1 °C | 34.04 mm |
| October | -0.4 °C | 14.9 °C | 22.61 mm |
| November | -8 °C | 4.7 °C | 13.21 mm |
| December | -14.1 °C | -2.3 °C | 10.41 mm |
| Annual | -1.4 °C | 13.4 °C | 373.4 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 3b : -37.2°C to -34.4°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |