Recent AEMET guidance and ensemble model runs indicate an overnight minimum near 17–19°C in Madrid on September 26 under partly cloudy skies and light variable winds, supporting the near-even market split between sub-16°C and 26°C+ outcomes. Radiative cooling rates will depend on cloud cover timing and boundary-layer moisture, with official forecasts showing little change from recent days and no strong advection of cooler or warmer air masses. Historical late-September climatology for the city center places typical lows around 15–18°C, but current high-pressure dominance and low precipitation probability reduce the chance of significant departures. Updated model cycles and AEMET briefings through the evening of the 25th remain the key data points likely to refine trader positioning before resolution.