Steptoe, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 36.7 °F (low) to 59.2 °F (high). Annual precipitation averages 20.7 Inches. Steptoe is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 25.9 °F | 37.5 °F | 2.69 in. |
| February | 26.9 °F | 41.8 °F | 1.95 in. |
| March | 30.7 °F | 49.4 °F | 2.24 in. |
| April | 35.1 °F | 57.1 °F | 1.84 in. |
| May | 41.3 °F | 66.3 °F | 1.86 in. |
| June | 46.3 °F | 72.4 °F | 1.37 in. |
| July | 50.1 °F | 83.8 °F | 0.51 in. |
| August | 49.8 °F | 84.7 °F | 0.48 in. |
| September | 43.4 °F | 75.1 °F | 0.63 in. |
| October | 35.9 °F | 60.2 °F | 1.67 in. |
| November | 30.4 °F | 45.2 °F | 2.58 in. |
| December | 25.1 °F | 36.3 °F | 2.92 in. |
| Annual | 36.7 °F | 59.2 °F | 20.74 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°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 |