Latest forecast models from agencies including AEMET and GFS consensus indicate a minimum temperature near 17°C for Madrid on September 26, driven by light variable winds, partly cloudy skies, and moderate radiative cooling overnight under high pressure. This setup creates tight market odds between a sub-16°C low—possible with clearer skies and stronger surface cooling—and a 26°C+ floor if cloud cover or urban heat retention limits the drop. Historical September averages around 14°C provide context, yet current warm advection from the south keeps overnight values elevated. Traders weigh the next model runs and surface observations for resolution thresholds.