Colfax, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 37.8 °F (low) to 60.5 °F (high). Annual precipitation averages 19.7 Inches. Colfax is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 26.9 °F | 38.6 °F | 2.59 in. |
| February | 28.0 °F | 43.2 °F | 1.97 in. |
| March | 31.8 °F | 50.8 °F | 2.2 in. |
| April | 36.2 °F | 58.6 °F | 1.76 in. |
| May | 42.3 °F | 67.8 °F | 1.67 in. |
| June | 47.2 °F | 73.8 °F | 1.23 in. |
| July | 51.3 °F | 85.1 °F | 0.46 in. |
| August | 50.9 °F | 85.8 °F | 0.42 in. |
| September | 44.6 °F | 76.4 °F | 0.5 in. |
| October | 37.1 °F | 61.4 °F | 1.48 in. |
| November | 31.4 °F | 46.4 °F | 2.52 in. |
| December | 26.0 °F | 37.5 °F | 2.92 in. |
| Annual | 37.8 °F | 60.5 °F | 19.72 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |