Forecasts from the National Weather Service and multiple models show Sunday's high in Seattle clustering in the low to mid-70s, driven by an approaching upper-level low that has cooled the air mass after recent warmer days while allowing gradual clearing of morning stratus and high clouds. Light northerly winds and residual marine moisture limit full solar heating, keeping temperatures below the August climatological average of around 76°F and capping upside potential. Ensemble spread and timing differences in cloud dissipation create roughly equal market-implied odds across the 68–75°F bins, with only low probability assigned to 78°F+ outcomes that would require stronger ridging or faster clearing than currently indicated. Updated model runs and afternoon observations will refine the exact peak before resolution.