Clinton, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.1 °C (low) to 13.7 °C (high). Annual precipitation averages 490 Millimeters. Clinton is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.4 °C | 0.1 °C | 31.75 mm |
| February | -8.3 °C | 2.9 °C | 33.78 mm |
| March | -5 °C | 8.3 °C | 39.12 mm |
| April | -1.6 °C | 13.1 °C | 40.64 mm |
| May | 2.3 °C | 18.4 °C | 54.36 mm |
| June | 6.1 °C | 22.6 °C | 68.58 mm |
| July | 8.4 °C | 29.3 °C | 27.43 mm |
| August | 7.6 °C | 29 °C | 28.7 mm |
| September | 3.5 °C | 22.7 °C | 36.83 mm |
| October | -1.1 °C | 13.4 °C | 42.16 mm |
| November | -5.7 °C | 4.7 °C | 50.29 mm |
| December | -9.5 °C | -0.7 °C | 36.32 mm |
| Annual | -1.1 °C | 13.7 °C | 489.96 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |