**Recent forecast model consensus and official guidance point to a notably cooler-than-average day in São Paulo on August 10, driving market-implied probabilities toward the 17–19°C range.** Numerical weather prediction models and data from Brazil’s National Institute of Meteorology (INMET) indicate a daytime maximum near 17–18°C under overcast skies and a post-frontal high-pressure regime featuring northeasterly winds and limited solar insolation. This follows a brief warm spell on August 9 (highs near 24°C) as a cold front passes, suppressing temperatures well below the August climatological average of 22–24°C. Key variables include cloud cover that reduces daytime heating, light winds limiting mixing, and the subtropical winter baseline of cooler, drier air masses. Resolution hinges on official INMET station readings for the daily maximum; any unexpected clearing or model shift could push outcomes toward 19–20°C, while persistent stratus or stronger advection would favor 17°C or lower. Traders are weighting the latest model runs and guidance heavily, creating tight clustering around the leading outcomes.