Recent forecasts from the National Weather Service and other models indicate a low near 53–55°F for Seattle on September 29, driven by an incoming frontal system with southerly winds, cloud cover, and light rain that limits radiational cooling. This marine-modified air mass typically moderates overnight minima compared to clear, calm conditions. However, the closely matched market odds on extremes below 47°F or above 66°F reflect uncertainty in exact timing of precipitation, wind shifts, and any model spread in boundary-layer processes. Historical late-September averages near 51°F provide context, with upcoming NWS updates and refined model runs likely to tighten the range around the mid-50s.