**Recent forecasts from NOAA-aligned sources and local models point to a high in the mid-to-upper 60s for Seattle on Friday, September 4, 2026, with partly sunny skies, light winds, and only a slight chance of drizzle.** This places the most probable outcome near the market’s leading bins (66–69 °F at ~39.5 % combined implied probability), well below the late-summer climatological average of ~73 °F. A persistent upper-level low and associated marine layer have kept daytime temperatures suppressed across the Pacific Northwest since early September. Onshore flow and lingering cloud cover from mid-week showers limit solar heating, while light northerly or variable winds reduce mixing that could otherwise allow brief warming. Ensemble guidance shows modest spread in the exact peak, with some runs favoring a touch more sun and a 68–69 °F high, while others keep thicker cloud decks and cap readings near 65–66 °F. The narrow clustering of the top two bins reflects this genuine forecast uncertainty: small differences in cloud timing or boundary-layer moisture can shift the daily maximum by 2–3 °F. With resolution hinging on official Seattle-Tacoma Airport observations, traders are weighting the current model consensus and recent below-normal trends more heavily than seasonal norms.