Recent short-range forecast models indicate a cooling trend into October 1 driven by an approaching frontal system that increases cloud cover and precipitation chances over Sao Paulo, limiting peak solar heating after several days of 34–35°C highs. This setup favors daily maxima clustering between 24–27°C, consistent with the tightly grouped market-implied probabilities around those levels and October’s climatological average high near 24°C. Key differentiating variables include the precise timing of rainfall onset, boundary-layer moisture, and steering flow strength, which can shift the realized maximum by 2–3°C across ensemble members. Updated model runs and official monitoring from agencies like INMET will refine these thresholds ahead of market resolution.