Sudden Valley, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 42.6 °F (low) to 57.6 °F (high). Annual precipitation averages 46.7 Inches. Sudden Valley is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 32.2 °F | 43.5 °F | 6.26 in. |
| February | 33.6 °F | 46.5 °F | 3.31 in. |
| March | 36.1 °F | 51.5 °F | 5.19 in. |
| April | 40.1 °F | 55.7 °F | 3.81 in. |
| May | 45.6 °F | 63.0 °F | 2.81 in. |
| June | 50.8 °F | 66.8 °F | 2.13 in. |
| July | 54.8 °F | 73.1 °F | 1.12 in. |
| August | 54.8 °F | 74.2 °F | 1.12 in. |
| September | 49.7 °F | 68.4 °F | 2.5 in. |
| October | 43.7 °F | 57.7 °F | 5.31 in. |
| November | 36.8 °F | 48.4 °F | 6.9 in. |
| December | 32.8 °F | 42.7 °F | 6.2 in. |
| Annual | 42.6 °F | 57.6 °F | 46.66 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8a : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |