Recent National Weather Service forecasts and ensemble model guidance indicate a high temperature in the low 70s for Seattle on August 28, with most runs converging on 70–72°F under mostly cloudy morning conditions giving way to partial afternoon sun, light southwesterly winds, and minimal marine layer influence. This consensus underpins the market’s heaviest weighting on the 72–73°F and 70–71°F bins at 40% and 29% implied probability. A modest chance of light showers may slightly suppress daytime maxima but is not expected to shift the outcome outside the 68–75°F range. Historical late-August climatology for the region, with typical highs near 76°F, supports the current cooler outlook driven by persistent onshore flow. Updated NWS briefings and model runs tonight will provide the final inputs before resolution.