Recent forecasts from the National Weather Service and other models point to sunny conditions over Seattle on September 27 following a cool frontal passage, supporting market-implied odds clustered around 64–67°F. High pressure rebuilding offshore favors clear skies and light winds, allowing modest daytime warming from morning lows near 45°F, though persistent marine influence from the Pacific keeps maxima well below seasonal averages near 70°F. Minor differences between the leading 64–65°F and 66–67°F bins hinge on exact peak timing, boundary-layer mixing, and whether official readings at Sea-Tac reach the higher end of model guidance. Updated NWS briefings and ensemble runs in the next 48 hours will refine these thresholds ahead of market resolution.