Choteau, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -0.4 °C (low) to 13.7 °C (high). Annual precipitation averages 304.6 Millimeters. Choteau is located in USDA Plant Hardiness Zone 4b. 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 | -9.8 °C | 2.2 °C | 7.87 mm |
| February | -9.6 °C | 3.2 °C | 10.41 mm |
| March | -5.8 °C | 7.4 °C | 13.21 mm |
| April | -1.4 °C | 12.4 °C | 29.97 mm |
| May | 3.4 °C | 17.6 °C | 50.55 mm |
| June | 7.4 °C | 21.8 °C | 70.87 mm |
| July | 10.3 °C | 27.6 °C | 25.91 mm |
| August | 9.4 °C | 27.2 °C | 27.18 mm |
| September | 5.3 °C | 21.6 °C | 30.23 mm |
| October | 0.1 °C | 14.2 °C | 19.81 mm |
| November | -5 °C | 7 °C | 10.92 mm |
| December | -9.1 °C | 2.6 °C | 7.62 mm |
| Annual | -0.4 °C | 13.7 °C | 304.55 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 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |