Traders assign the highest implied probabilities to 26°C (46%) and 27°C (28.5%) for São Paulo’s maximum temperature on August 4 because official forecasts from agencies such as the Met Office and numerical models currently project a daytime high near 26–28°C under stable subtropical winter conditions. In the Southern Hemisphere’s dry season, clear skies and light winds favor modest daytime warming, while the urban heat island effect in the metropolitan area can add 1–2°C relative to surrounding rural baselines. Recent observations show highs of 25–29°C over the prior days with minimal rainfall, supporting model consensus around these values rather than cooler seasonal averages near 23°C or rarer warmer outliers. Updated model runs and any late adjustments from regional meteorological services remain the key near-term catalysts.