Addy, Washington has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.5 °C (low) to 15.3 °C (high). Annual precipitation averages 533.2 Millimeters. Addy is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.5 °C | 0.9 °C | 60.71 mm |
| February | -5.1 °C | 4.8 °C | 41.15 mm |
| March | -2.2 °C | 10.2 °C | 53.59 mm |
| April | 0.4 °C | 15.3 °C | 38.35 mm |
| May | 4.6 °C | 20.7 °C | 51.31 mm |
| June | 7.6 °C | 24.1 °C | 55.12 mm |
| July | 10.1 °C | 30.1 °C | 21.08 mm |
| August | 9.4 °C | 30.3 °C | 14.99 mm |
| September | 5.5 °C | 24.6 °C | 20.83 mm |
| October | 0.9 °C | 15.3 °C | 40.39 mm |
| November | -2.3 °C | 6 °C | 61.98 mm |
| December | -5.7 °C | 0.9 °C | 73.66 mm |
| Annual | 1.5 °C | 15.3 °C | 533.16 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 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 | Dfb - Humid Continental Mild Summer, Wet All Year |