Latest ensemble forecasts from global and regional models, including those informing INMET guidance, point to Sao Paulo's overnight minimum on October 12 settling near 18–19 °C under persistent cloud cover, scattered showers, and light easterly flow associated with a frontal boundary. These conditions limit radiational cooling while suppressing daytime heating that could otherwise elevate the daily low. Model spread remains modest, with most solutions clustering between 17–20 °C, explaining the near-even market-implied odds across the 16–22 °C range. Updated high-resolution runs and the next official INMET bulletin will provide the final observational constraints before resolution.