Hazel Dell, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 43.6 °F (low) to 62.5 °F (high). Annual precipitation averages 42.2 Inches. Hazel Dell is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 34.9 °F | 46.7 °F | 6.02 in. |
| February | 35.0 °F | 50.6 °F | 4.14 in. |
| March | 37.7 °F | 55.5 °F | 4.72 in. |
| April | 41.0 °F | 60.3 °F | 3.42 in. |
| May | 46.6 °F | 67.4 °F | 2.65 in. |
| June | 50.8 °F | 72.1 °F | 1.83 in. |
| July | 54.8 °F | 79.6 °F | 0.52 in. |
| August | 54.8 °F | 80.7 °F | 0.6 in. |
| September | 50.3 °F | 75.0 °F | 1.62 in. |
| October | 44.0 °F | 63.4 °F | 3.83 in. |
| November | 38.6 °F | 52.6 °F | 5.99 in. |
| December | 34.6 °F | 46.0 °F | 6.89 in. |
| Annual | 43.6 °F | 62.5 °F | 42.23 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |