**Forecast consensus from National Weather Service and multiple models positions the highest temperature in Seattle on August 26, 2026, in the mid-to-upper 70s.** Official NWS guidance highlights upper-level ridging over the Pacific Northwest maintaining mostly sunny skies and southwesterly flow, with highs in the 70s to lower 80s after Tuesday’s warmer peak. Multiple sources converge on 74–82°F, with specific point forecasts clustering near 75–76°F (WeatherBug, WindBorne) or slightly higher at 82°F in some updates. Scientific drivers include daytime solar heating under partly cloudy to sunny conditions, moderated by onshore marine influence and light winds that limit extreme warming. The long-term August 26 climatological average high of 75.5°F provides context, while recent regional ridging has supported above-normal readings without pushing into record territory. Minor smoke advection from wildfires may slightly suppress maximums by reducing insolation. Market-implied odds heavily favor 78–79°F (41.5%) and 76–77°F (29.5%), reflecting trader weighting of the tight forecast envelope and limited expected spread in model runs. Lower probabilities for 80–81°F (16.5%) account for upside uncertainty if skies clear more than anticipated, while sub-75°F outcomes remain discounted given persistent warmth. Updated NWS briefings and afternoon model guidance on the 25th represent the key near-term catalysts that could refine these implied probabilities ahead of resolution.