Leavenworth, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 3.4 °C (low) to 16.3 °C (high). Annual precipitation averages 530.3 Millimeters. Leavenworth is located in USDA Plant Hardiness Zone 7a. 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 | -4.8 °C | 1.7 °C | 80.52 mm |
| February | -3.7 °C | 5.9 °C | 62.23 mm |
| March | -0.7 °C | 11.2 °C | 57.91 mm |
| April | 2.3 °C | 16.6 °C | 23.11 mm |
| May | 6.5 °C | 22 °C | 24.38 mm |
| June | 9.9 °C | 25.4 °C | 18.29 mm |
| July | 13.2 °C | 30.7 °C | 6.6 mm |
| August | 12.8 °C | 30.7 °C | 8.89 mm |
| September | 8.2 °C | 25.7 °C | 12.95 mm |
| October | 2.8 °C | 17 °C | 53.34 mm |
| November | -1.4 °C | 7.3 °C | 84.07 mm |
| December | -4.8 °C | 1.5 °C | 98.04 mm |
| Annual | 3.4 °C | 16.3 °C | 530.33 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 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |