Forecast models from NOAA and others point to Seattle's overnight low on October 13 falling in the mid-40s to low 50s, driven by a building upper-level ridge supporting mild Pacific air, light southerly flow, and increasing cloud cover that limits radiative cooling. Traders favor 54°F or higher or 44-45°F as the tightest outcomes because ensemble guidance shows modest spread in boundary-layer moisture and wind speeds, which can shift minimums by several degrees; clearer conditions would favor sharper drops toward the lower bracket while persistent clouds hold readings higher. Historical October averages near 47°F provide context, but current dry northerly aloft flow and lack of strong cold advection keep sub-40°F probabilities minimal. Updated model runs tonight will clarify the exact minimum.