Green Bluff, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 2.8 °C (low) to 14.3 °C (high). Annual precipitation averages 606.1 Millimeters. Green Bluff is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.4 °C | 1.6 °C | 73.66 mm |
| February | -3.9 °C | 4.2 °C | 52.07 mm |
| March | -1.3 °C | 9 °C | 63.25 mm |
| April | 1.5 °C | 13.6 °C | 50.29 mm |
| May | 5.7 °C | 19 °C | 51.31 mm |
| June | 8.8 °C | 22.5 °C | 52.07 mm |
| July | 11.9 °C | 28.5 °C | 15.49 mm |
| August | 11.7 °C | 28.7 °C | 16.26 mm |
| September | 7.4 °C | 23.1 °C | 22.1 mm |
| October | 2.2 °C | 14.4 °C | 49.28 mm |
| November | -1.6 °C | 6.1 °C | 75.18 mm |
| December | -4.6 °C | 1.1 °C | 85.09 mm |
| Annual | 2.8 °C | 14.3 °C | 606.05 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |