**Forecast models for Madrid on August 26 point to a minimum temperature near the long-term average of 18.5°C, with ensemble spreads producing closely matched market-implied probabilities across the 14–18°C bins.** Overnight radiative cooling under partly to mostly cloudy skies, combined with moderate southwest winds of 5–15 km/h and dew points near 9–11°C, will limit how far temperatures drop after sunset. High pressure maintains generally stable conditions, while variable cloud cover introduces the main uncertainty in how effectively heat radiates away. Recent observations show August 2026 minima mostly in the 18–22°C range, with a cooler 18.9°C reading mid-month, keeping the forecast anchored near climatology rather than extremes. Slight cooling is expected ahead of a more pronounced drop on the 27th. The tight clustering of trader probabilities around 16–18°C (with 14°C or below also competitive) directly reflects this model uncertainty in cloud timing and wind-driven mixing, typical for a single-day minimum forecast one day out. New model runs and observational updates overnight will likely refine the exact outcome.