Recent National Weather Service and ensemble model guidance points to an overnight low for Seattle on September 4 near the seasonal norm of 54–55 °F, with most runs clustering in the lower-to-mid 50s under partly to mostly cloudy skies and light winds. Persistent marine influence from Puget Sound, combined with modest southerly flow and elevated dew points near 52–54 °F, limits radiational cooling and keeps the boundary layer from dropping sharply. Trader consensus around the 52–55 °F bins reflects small but meaningful uncertainty in cloud-cover timing and any late-night clearing that could allow an extra degree or two of cooling, while the modest probability on 50–51 °F or lower captures the tail risk of clearer, calmer conditions. Historical analogs for early-September nights with similar synoptic setups show minima rarely falling below 50 °F without stronger high-pressure ridging or northerly advection, keeping the market tightly bunched in the low-to-mid 50s.