Renton experiences a Mediterranean-influenced Marine West Coast climate (Köppen classification Csb). The region is famous for its mild temperatures, wet winters, and warm, dry summers.
Summers are exceptionally pleasant, with July and August seeing average high temperatures around 76°F to 79°F (24°C–26°C) and very little rainfall, making this the best time to visit. Winters are cool, cloudy, and damp, with average daytime highs around 46°F (8°C) and overnight lows near 35°F (2°C). Renton receives about 39 inches of rain annually, primarily between October and April. Snowfall is generally light and infrequent, averaging just a few inches per year, though occasional winter storms can bring temporary accumulation.