**Forecasts for Seattle’s overnight low on September 2, 2026, cluster tightly in the mid-50s °F, aligning with the market’s leading outcomes near 55–57 °F (historical September 2 average low is 55.1 °F).** Multiple model runs and agency outlooks project a low of 55–56 °F under mostly cloudy skies with periods of rain and south-southwest winds of 10–20 mph. These conditions limit radiational cooling that would otherwise drop temperatures further on clear, calm nights. Cloud cover and precipitation reduce the diurnal temperature range by trapping longwave radiation and adding latent heat, while moderate winds promote mixing that prevents sharp surface cooling. An approaching frontal system introduces uncertainty in exact timing and intensity, which can shift the minimum by a few degrees depending on whether heavier rain arrives before or after the typical pre-dawn minimum. This explains the near-even market pricing across the 52–59 °F bins and the lower probabilities assigned to extremes below 50 °F or above 64 °F. Traders appear to be weighting the consensus of short-range numerical weather prediction guidance against climatology, with the slight edge to 56–57 °F reflecting the most recent model consensus that keeps the low just above the long-term average despite the unsettled pattern. Updated forecast discussions from the National Weather Service and new model runs ahead of the event remain the key near-term catalysts that could shift probabilities within these narrow ranges.