Grays River, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 5.5 °C (low) to 15.9 °C (high). Annual precipitation averages 2570.7 Millimeters. Grays River 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 Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.9 °C | 9 °C | 410.21 mm |
| February | 1.4 °C | 10.6 °C | 248.92 mm |
| March | 2.4 °C | 12.3 °C | 289.81 mm |
| April | 3.8 °C | 14.8 °C | 198.63 mm |
| May | 6.6 °C | 17.9 °C | 109.22 mm |
| June | 8.8 °C | 19.8 °C | 89.41 mm |
| July | 10.8 °C | 22.9 °C | 27.69 mm |
| August | 10.8 °C | 23.6 °C | 44.2 mm |
| September | 8.9 °C | 22.2 °C | 100.08 mm |
| October | 5.8 °C | 16.9 °C | 246.89 mm |
| November | 3.2 °C | 11.6 °C | 396.49 mm |
| December | 1.6 °C | 8.6 °C | 409.19 mm |
| Annual | 5.5 °C | 15.9 °C | 2570.74 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |