Forecast models, including recent GFS and Met Office guidance, place Madrid’s overnight low on August 26 near 15–17 °C, consistent with late-August climatology of roughly 16–18 °C at the Adolfo Suárez Madrid-Barajas reference station. Clear or partly cloudy skies under a weakening high-pressure ridge promote efficient nocturnal radiative cooling, while light south-westerly winds limit mixing and allow surface temperatures to drop close to the dew-point. Minor forecast spread arises from uncertainty in cloud cover and any weak frontal moisture arriving from the Atlantic; a modest increase in low-level humidity or breeze could hold the minimum near 18–19 °C, whereas clearer, calmer conditions favor 15–16 °C. Traders therefore assign the highest probabilities to the tightly grouped 16–19 °C outcomes, reflecting model consensus tempered by typical 1–2 °C run-to-run variability two days from resolution.