Chelan, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 40.6 °F (low) to 61.2 °F (high). Annual precipitation averages 11.1 Inches. Chelan is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 24.1 °F | 33.9 °F | 1.59 in. |
| February | 26.8 °F | 41.0 °F | 1.0 in. |
| March | 32.8 °F | 52.2 °F | 1.06 in. |
| April | 39.1 °F | 62.1 °F | 0.8 in. |
| May | 46.5 °F | 72.1 °F | 0.91 in. |
| June | 52.7 °F | 78.6 °F | 0.71 in. |
| July | 58.9 °F | 88.1 °F | 0.33 in. |
| August | 58.4 °F | 87.6 °F | 0.24 in. |
| September | 50.8 °F | 77.8 °F | 0.33 in. |
| October | 40.5 °F | 61.8 °F | 0.96 in. |
| November | 31.9 °F | 45.1 °F | 1.46 in. |
| December | 25.2 °F | 34.5 °F | 1.69 in. |
| Annual | 40.6 °F | 61.2 °F | 11.08 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7b : 5°F to 10°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |