Traders assign near-certainty to a 24°C high in Paris on August 22 because ensemble forecasts from the European Centre for Medium-Range Weather Forecasts and Météo-France have converged on that value, with tight clustering around afternoon peak readings under stable anticyclonic conditions. Official surface observations and model guidance show limited variability from typical late-August baselines, with no strong warm-air advection or clear-sky amplification expected. Minor remaining uncertainty stems from possible localized cloud development or station-specific microclimate effects at Paris-Montsouris, but these are unlikely to alter the daily maximum enough to change resolution. New model runs or real-time station data later today represent the primary catalysts that could still shift the narrow tail probabilities.