Seattle Faces First Muggy Summer in a Generation as Super El Niño Odds Near 90%
Updated
Updated · MyNorthwest · Jun 17
Seattle Faces First Muggy Summer in a Generation as Super El Niño Odds Near 90%
1 articles · Updated · MyNorthwest · Jun 17
Summary
Daniel Swain warned Seattle could see its first notably muggy summer in decades, with sticky afternoons and unusually warm nights replacing the city’s typical dry summer cooldown.
Nearly 90% odds of a strong El Niño and better than 60% odds of a very strong one by autumn, combined with a northeast Pacific marine heatwave, are expected to pump extra water vapor into West Coast air.
Upper-70s to mid-80s days may pose the bigger strain than extreme heat because humidity can keep homes from cooling overnight, undermining Seattle’s common open-window strategy in a region where many homes still lack air conditioning.
Swain also flagged higher odds of blocking ridges, heatwaves and fire-weather risks, including southerly flow that could bring monsoon moisture and thunderstorms into Eastern Washington.
The warning carries added weight after Seattle hit 108F in the 2021 heat dome, which killed more than 100 people in Washington, though Swain said this summer’s main threat is humidity rather than record dry heat.
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2026 “Super” El Niño Set to Rewrite Seattle’s Summer: Humidity, Drought, and Wildfire Risks Surge in the Pacific Northwest
Overview
Seattle is preparing for a summer unlike any in recent memory, as 2026 is expected to bring the city its first truly muggy season. This shift marks a major departure from Seattle’s usual dry summers, with forecasts predicting warmer and drier conditions across the Pacific Northwest. A meager winter snowpack and existing drought in Eastern Washington mean Western Washington is also likely to face drought. The combination of rising temperatures and increasing drought risk sets the stage for an unprecedented summer, making the predicted humidity especially significant for Seattleites.