Forecast models for São Paulo on August 25, 2026, converge on a daytime maximum near 20–22°C under mostly cloudy skies and light southeasterly flow, aligning with the market’s concentration of probability around 21°C (33%) and 22°C (20.5%). Persistent wintertime high pressure and limited insolation from cloud cover are suppressing peak temperatures below late-August climatological norms of 21–23°C. Key variables include the strength and timing of any passing cold front, which could cap the high near 19–20°C, versus clearer intervals that might allow brief warming to 23°C. Official guidance from regional models shows modest spread, leaving room for intraday shifts in boundary-layer mixing and radiative cooling. Traders appear to weigh these near-term atmospheric conditions heavily, with lower-probability tails reflecting the low likelihood of significant deviations on this date.