Clark Fork, Idaho has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 1.8 °C (low) to 14 °C (high). Annual precipitation averages 789.9 Millimeters. Clark Fork is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.8 °C | 1.2 °C | 99.57 mm |
| February | -4.7 °C | 3.8 °C | 64.26 mm |
| March | -2.3 °C | 8.6 °C | 77.72 mm |
| April | 0.7 °C | 13.7 °C | 56.64 mm |
| May | 4.5 °C | 19.3 °C | 71.63 mm |
| June | 7.9 °C | 22.6 °C | 71.88 mm |
| July | 10.1 °C | 28.3 °C | 25.15 mm |
| August | 9.5 °C | 28.4 °C | 21.34 mm |
| September | 5.7 °C | 22.4 °C | 33.53 mm |
| October | 1.6 °C | 13.5 °C | 71.37 mm |
| November | -1.7 °C | 5.4 °C | 96.77 mm |
| December | -4.7 °C | 0.9 °C | 100.08 mm |
| Annual | 1.8 °C | 14 °C | 789.94 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |