Current forecasts from multiple meteorological models indicate radiational cooling under clear skies will drive Madrid’s overnight low into the mid-teens Celsius, consistent with the market’s near-certain consensus on 16 °C or below. Official guidance and ensemble outputs show minimums of 16–18 °C, with the lower end favored by dry air, light winds, and surface conditions typical for late September in central Spain. Historical climatology places average September minima near 16 °C, providing additional context for the strong trader positioning. A realistic scenario that could shift resolution higher would require unexpected cloud cover or a warmer air mass arriving earlier than modeled, though current observations show no such development. Updated short-range model runs and final station readings will confirm the exact minimum before market settlement.