Recent forecasts from multiple models indicate a cooler air mass advecting into São Paulo, producing daytime highs near 18–21°C and favoring strong nocturnal radiative cooling under mostly clear skies with light southeast winds. This setup supports minimum temperatures clustering tightly between 10–12°C on August 22, driving the closely matched market probabilities. Minor differences among leading outcomes stem from uncertainty in exact cloud cover timing and boundary-layer mixing, which can alter the overnight low by 1–2°C; official meteorological agencies will issue updated model runs and observations through the night that traders are monitoring closely for resolution.