Recent NOAA and NWS ensemble forecasts for Seattle on October 1 project overnight lows of 46–52°F, shaped by moderate southerly flow, patchy marine layer influence, and variable cloud cover that limits radiational cooling. This aligns with the historical average low of 49.9°F while recent years have ranged from the low 40s to mid-50s under similar early-fall patterns. Model consensus shows modest spread in minimum timing and intensity, supporting closely matched market probabilities around 48–49°F versus higher bins, with limited downside risk below 45°F absent a stronger cold-air intrusion. Updated model runs and local observations over the next 48 hours will refine the exact threshold.