Weeksville, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.6 °C (low) to 15.5 °C (high). Annual precipitation averages 345.7 Millimeters. Weeksville is located in USDA Plant Hardiness Zone 6a. 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 | -5.6 °C | 2 °C | 29.97 mm |
| February | -4.9 °C | 4.8 °C | 23.62 mm |
| March | -2.7 °C | 9.9 °C | 23.88 mm |
| April | 0.3 °C | 14.9 °C | 31.5 mm |
| May | 4.2 °C | 20.6 °C | 37.34 mm |
| June | 7.8 °C | 24.3 °C | 49.53 mm |
| July | 10.5 °C | 30.8 °C | 19.05 mm |
| August | 10.1 °C | 30.8 °C | 16.26 mm |
| September | 6.1 °C | 24.5 °C | 23.11 mm |
| October | 1.2 °C | 15.1 °C | 30.48 mm |
| November | -2.6 °C | 6.2 °C | 32 mm |
| December | -5.3 °C | 1.5 °C | 28.96 mm |
| Annual | 1.6 °C | 15.5 °C | 345.7 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 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |