**Recent model consensus from European weather services points to overnight lows in Paris near 15–17°C on August 20, 2026, aligning with the market’s heavy clustering on those outcomes.** A transition to cooler maritime Atlantic air, increased cloud cover, and scattered showers are limiting radiational cooling while keeping minimum temperatures mild for late summer. Météo-France and ECMWF guidance highlight westerly flow and light winds that reduce the typical nocturnal drop, with forecast lows centered around 15–16°C under partly cloudy skies. Climatological context reinforces this range: mid-August average lows in the Paris basin sit near 14–15°C, and the current pattern shows only modest deviation from seasonal norms despite earlier heat. Traders appear to price the highest probability at 16°C because ensemble spreads remain tight, with only small upside risk for 17°C or downside to 14°C if clearer skies develop overnight. Upcoming short-range model runs and Météo-France updates on August 19 will likely refine these probabilities as the 48-hour window narrows.