Sunnyslope, Washington has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 40.5 °F (low) to 62.5 °F (high). Annual precipitation averages 9.8 Inches. Sunnyslope is located in USDA Plant Hardiness Zone 7a. 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 | 24.8 °F | 35.9 °F | 1.48 in. |
| February | 27.2 °F | 43.5 °F | 1.03 in. |
| March | 32.5 °F | 53.8 °F | 0.87 in. |
| April | 38.8 °F | 63.5 °F | 0.64 in. |
| May | 46.6 °F | 72.8 °F | 0.78 in. |
| June | 53.1 °F | 79.3 °F | 0.64 in. |
| July | 59.2 °F | 88.8 °F | 0.3 in. |
| August | 58.4 °F | 88.2 °F | 0.18 in. |
| September | 50.1 °F | 78.9 °F | 0.29 in. |
| October | 39.5 °F | 63.1 °F | 0.76 in. |
| November | 31.0 °F | 46.6 °F | 1.16 in. |
| December | 25.2 °F | 35.8 °F | 1.65 in. |
| Annual | 40.5 °F | 62.5 °F | 9.78 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 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |