Tukwila, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 7.3 °C (low) to 16.1 °C (high). Annual precipitation averages 1060.7 Millimeters. Tukwila is located in USDA Plant Hardiness Zone 9a. 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 | 2.5 °C | 8.7 °C | 141.99 mm |
| February | 2.5 °C | 10.1 °C | 103.89 mm |
| March | 3.9 °C | 12.3 °C | 117.09 mm |
| April | 5.8 °C | 15.1 °C | 88.14 mm |
| May | 8.8 °C | 18.9 °C | 50.29 mm |
| June | 11.3 °C | 21.3 °C | 44.45 mm |
| July | 13.3 °C | 24.8 °C | 19.05 mm |
| August | 13.4 °C | 25.1 °C | 24.13 mm |
| September | 11.2 °C | 21.9 °C | 41.4 mm |
| October | 7.7 °C | 16 °C | 111.76 mm |
| November | 4.4 °C | 11.2 °C | 163.32 mm |
| December | 2.3 °C | 8.2 °C | 155.19 mm |
| Annual | 7.3 °C | 16.1 °C | 1060.7 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 30-40 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |