Maple Valley, Washington has a Temperate Oceanic Climate climate (Köppen classification: Cfb). Average annual temperatures range from 43.2 °F (low) to 60.2 °F (high). Annual precipitation averages 49.6 Inches. Maple Valley is located in USDA Plant Hardiness Zone 8b. 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 | 35.0 °F | 46.3 °F | 6.34 in. |
| February | 34.9 °F | 49.0 °F | 4.71 in. |
| March | 37.1 °F | 53.1 °F | 5.35 in. |
| April | 40.5 °F | 58.2 °F | 4.46 in. |
| May | 46.0 °F | 65.6 °F | 2.89 in. |
| June | 50.3 °F | 69.8 °F | 2.54 in. |
| July | 53.9 °F | 76.5 °F | 1.06 in. |
| August | 54.1 °F | 77.0 °F | 1.38 in. |
| September | 50.0 °F | 70.8 °F | 2.32 in. |
| October | 43.7 °F | 59.8 °F | 5.05 in. |
| November | 38.3 °F | 50.9 °F | 7.08 in. |
| December | 34.4 °F | 45.2 °F | 6.4 in. |
| Annual | 43.2 °F | 60.2 °F | 49.58 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| 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 | Normal |
| Köppen Climate Classification | Cfb - Temperate Oceanic Climate |