Manhattan, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -1 °C (low) to 14.4 °C (high). Annual precipitation averages 331.2 Millimeters. Manhattan 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 | -10.8 °C | 1.1 °C | 11.94 mm |
| February | -9.3 °C | 3.1 °C | 13.21 mm |
| March | -5.4 °C | 8.6 °C | 19.3 mm |
| April | -1.4 °C | 13.3 °C | 32.26 mm |
| May | 3.3 °C | 18.6 °C | 55.12 mm |
| June | 7.2 °C | 23.5 °C | 64.77 mm |
| July | 10.1 °C | 29.7 °C | 30.23 mm |
| August | 8.6 °C | 29.2 °C | 22.86 mm |
| September | 4.4 °C | 23.2 °C | 27.43 mm |
| October | -1 °C | 14.8 °C | 24.89 mm |
| November | -6.6 °C | 6.6 °C | 17.02 mm |
| December | -10.8 °C | 1 °C | 12.19 mm |
| Annual | -1 °C | 14.4 °C | 331.22 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 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |