**Forecast models for Seattle on August 27, 2026, converge on a high in the low-to-mid 70s°F, with morning marine-layer clouds giving way to partial sun under southwesterly flow.** Official guidance from sources like the National Weather Service and ensemble outputs points to highs near 70–75°F, aligning with the market's heaviest weighting on the 74–75°F (35%) and 72–73°F (27.5%) bins. Key differentiating factors include the strength and timing of cloud break-up, which controls peak solar heating, and the degree of onshore advection of cooler marine air from the Pacific. Stronger or more persistent low clouds would cap the high near 70–72°F by limiting insolation, while earlier clearing and lighter winds could allow readings to reach 76–77°F. Historical late-August normals around 75°F provide context, but current model runs show modest cooling relative to the prior day amid stable synoptic patterns. Traders appear to price the central bins most heavily because ensemble spread remains modest yet non-zero on exact cloud timing and boundary-layer mixing, with lower probabilities assigned to outliers that would require significant forecast errors. New model runs and afternoon observations on August 26 will likely refine the range ahead of resolution.