Recent meteorological model runs show tight clustering around 19–21°C for São Paulo’s maximum temperature on August 24, with ensemble spreads from agencies such as INMET and ECMWF reflecting modest uncertainty in boundary-layer conditions and frontal timing. A passing cold front and variable low-level moisture are the dominant variables, as small shifts in cloud cover or wind direction can alter daytime heating by 1–2°C in the subtropical winter regime. Urban heat-island effects and local topography add further microscale variability that dynamical models resolve differently across members. Traders therefore assign the highest implied probabilities to the central outcomes while discounting extremes, consistent with historical August variability and the short forecast horizon limiting additional data updates before resolution.