Deer Park, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 1.2 °C (low) to 14.7 °C (high). Annual precipitation averages 572.3 Millimeters. Deer Park is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.6 °C | 1.3 °C | 79.5 mm |
| February | -5.2 °C | 4.3 °C | 43.94 mm |
| March | -2.6 °C | 9.4 °C | 53.85 mm |
| April | 0.2 °C | 14.1 °C | 41.4 mm |
| May | 4.3 °C | 19.7 °C | 51.82 mm |
| June | 7.4 °C | 23.2 °C | 49.28 mm |
| July | 9.7 °C | 29.2 °C | 15.24 mm |
| August | 9.1 °C | 29.4 °C | 14.73 mm |
| September | 5.1 °C | 23.7 °C | 19.56 mm |
| October | 0.6 °C | 14.8 °C | 46.23 mm |
| November | -2.6 °C | 6 °C | 72.39 mm |
| December | -5.6 °C | 0.9 °C | 84.33 mm |
| Annual | 1.2 °C | 14.7 °C | 572.27 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°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 |