**Trader sentiment for Seattle's highest temperature on August 22, 2026, centers on the 70–73°F range (combined ~69.5% implied probability) because National Weather Service guidance and ensemble models project a moderate high driven by persistent onshore marine flow.** This typical late-summer pattern brings cooler, moister air from the Pacific, limiting afternoon warming and often producing low clouds or marine stratus that cap peaks near the seasonal average of ~75°F. Recent model runs show a cooler air mass and possible scattered showers or increased cloud cover for the 22nd, shifting expectations downward from earlier warmer analogs and aligning with NWS point forecasts around 71–72°F at Sea-Tac. Historical climatology reinforces this: late August highs frequently fall in the low-to-mid 70s when onshore winds dominate, reducing the chance of the 74°F+ outcomes that would require a stronger offshore or downslope component. Upcoming NWS forecast updates and the next model cycle will be the key catalysts for any further shifts in these market-implied odds.