Renton, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 45.4 °F (low) to 61.2 °F (high). Annual precipitation averages 41.4 Inches. Renton 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 | 36.7 °F | 47.7 °F | 5.57 in. |
| February | 36.8 °F | 50.2 °F | 4.11 in. |
| March | 39.3 °F | 54.1 °F | 4.54 in. |
| April | 42.8 °F | 59.3 °F | 3.52 in. |
| May | 48.2 °F | 66.2 °F | 1.9 in. |
| June | 52.7 °F | 70.6 °F | 1.64 in. |
| July | 56.3 °F | 76.8 °F | 0.68 in. |
| August | 56.5 °F | 77.4 °F | 0.96 in. |
| September | 52.6 °F | 71.7 °F | 1.57 in. |
| October | 46.2 °F | 60.9 °F | 4.3 in. |
| November | 40.3 °F | 52.3 °F | 6.5 in. |
| December | 36.4 °F | 46.9 °F | 6.08 in. |
| Annual | 45.4 °F | 61.2 °F | 41.37 in. |
| 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 : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |