Edison, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.3 °C (low) to 14.6 °C (high). Annual precipitation averages 911.6 Millimeters. Edison is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.2 °C | 7.9 °C | 127.76 mm |
| February | 2.1 °C | 8.9 °C | 81.28 mm |
| March | 3.4 °C | 10.9 °C | 91.95 mm |
| April | 5.2 °C | 13.7 °C | 70.61 mm |
| May | 7.7 °C | 17.1 °C | 57.15 mm |
| June | 10.1 °C | 19.4 °C | 41.91 mm |
| July | 11.3 °C | 22.1 °C | 22.86 mm |
| August | 11.2 °C | 22.6 °C | 25.65 mm |
| September | 9.5 °C | 19.6 °C | 45.72 mm |
| October | 6.6 °C | 14.6 °C | 95.5 mm |
| November | 4 °C | 10.4 °C | 138.18 mm |
| December | 1.9 °C | 7.6 °C | 113.03 mm |
| Annual | 6.3 °C | 14.6 °C | 911.6 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| 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 |