Recent meteorological forecasts from multiple models point to a daytime maximum of 25–26°C in São Paulo on August 21, driven by a post-frontal air mass with moderate westerly flow, partly cloudy skies, and low humidity limiting afternoon heating. Trader sentiment clusters tightly around these outcomes because ensemble guidance shows minor spreads in cloud cover and boundary-layer mixing, which can shift peak temperatures by 1°C through differences in solar insolation and urban heat-island effects. Historical August climatology (typical highs near 22–24°C) and the recent warm spell ending with a cold front reinforce the market’s narrow distribution, while ongoing model updates from agencies like INMET keep resolution criteria focused on official station readings.