Seattle’s Saturday forecast is mostly cloudy, with a high near 55 degrees. Rain is expected to move into the city by Sunday morning, shifting the weekend from a cool, largely dry start to cloudy conditions with occasional light rain.
Rain Arrives Sunday; Clouds Continue Into Monday
Sunday is forecast to be cloudy with occasional light rain and a high near 56 degrees, according to the National Weather Service. A few showers could linger Sunday night. Monday has a slight chance of morning rain before partly sunny skies return in the afternoon.
The unsettled pattern is expected to continue early next week. Tuesday and Wednesday are forecast to be mostly cloudy with rain chances; Wednesday’s high is near 54 degrees, according to the National Weather Service. The forecast does not establish that heavier rain or flooding will occur.
Marine Advisory and Local Rainfall Context
Conditions on the water may be rougher than those on land: a Small Craft Advisory covers portions of the coastal waters and Strait of Juan de Fuca from Saturday into Sunday. The advisory concerns mariners, while the city forecast calls for occasional light rain.
Rain can matter to Seattle’s waterways even when a particular forecast does not establish an overflow risk. Seattle Public Utilities says about one third of the city has a combined sewer system that carries stormwater and wastewater together, and heavy rain makes overflows into local waters more likely. The city’s current wastewater permit also requires real-time online reporting of Seattle overflows, according to Seattle Public Utilities. Neither fact indicates that an overflow is expected this weekend.
A much more severe regional precedent shows why the distinction matters: the Center for Western Weather and Water Extremes at UC San Diego documented atmospheric rivers that brought heavy rainfall, flooding and landslides to the Pacific Northwest from Nov. 10–16, 2021. That was a separate event, not a forecast for Seattle this weekend, and it does not establish that similar impacts are expected now.
