Valley, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 34.3 °F (low) to 59.8 °F (high). Annual precipitation averages 21 Inches. Valley is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.8 °F | 33.9 °F | 2.63 in. |
| February | 22.4 °F | 40.8 °F | 1.75 in. |
| March | 27.7 °F | 50.7 °F | 2.2 in. |
| April | 32.8 °F | 60.0 °F | 1.54 in. |
| May | 40.3 °F | 69.9 °F | 1.9 in. |
| June | 45.8 °F | 75.8 °F | 1.82 in. |
| July | 49.6 °F | 86.4 °F | 0.72 in. |
| August | 48.1 °F | 86.8 °F | 0.5 in. |
| September | 41.0 °F | 76.5 °F | 0.7 in. |
| October | 32.7 °F | 60.1 °F | 1.66 in. |
| November | 27.9 °F | 43.5 °F | 2.59 in. |
| December | 21.5 °F | 33.7 °F | 2.99 in. |
| Annual | 34.3 °F | 59.8 °F | 21 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |