Townsend, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -0.1 °C (low) to 14.9 °C (high). Annual precipitation averages 264.4 Millimeters. Townsend 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 Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.3 °C | 1.2 °C | 6.86 mm |
| February | -8.3 °C | 4.2 °C | 5.84 mm |
| March | -4.9 °C | 9.6 °C | 10.67 mm |
| April | -0.6 °C | 14.6 °C | 22.1 mm |
| May | 4.1 °C | 19.5 °C | 43.43 mm |
| June | 8 °C | 23.8 °C | 64.01 mm |
| July | 10.9 °C | 29.6 °C | 30.23 mm |
| August | 9.6 °C | 29.1 °C | 27.69 mm |
| September | 5.3 °C | 23.3 °C | 20.32 mm |
| October | -0.1 °C | 15.4 °C | 15.49 mm |
| November | -5.3 °C | 7 °C | 9.4 mm |
| December | -9.6 °C | 1.5 °C | 8.38 mm |
| Annual | -0.1 °C | 14.9 °C | 264.42 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| 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 |