Federal Way, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.4 °C (low) to 15.8 °C (high). Annual precipitation averages 1251 Millimeters. Federal Way is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.8 °C | 8 °C | 179.07 mm |
| February | 1.8 °C | 9.4 °C | 125.48 mm |
| March | 3 °C | 11.7 °C | 144.53 mm |
| April | 4.8 °C | 14.8 °C | 100.33 mm |
| May | 7.8 °C | 18.8 °C | 59.94 mm |
| June | 10.2 °C | 21.2 °C | 50.04 mm |
| July | 12.3 °C | 24.9 °C | 21.84 mm |
| August | 12.4 °C | 25.2 °C | 32.77 mm |
| September | 10.2 °C | 21.9 °C | 55.88 mm |
| October | 6.7 °C | 15.8 °C | 124.97 mm |
| November | 3.7 °C | 10.6 °C | 178.82 mm |
| December | 1.6 °C | 7.4 °C | 177.29 mm |
| Annual | 6.4 °C | 15.8 °C | 1250.96 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 20-30 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 |