Forecast models from sources including the GFS and regional analyses indicate a minimum temperature near 19°C for São Paulo on September 27, driven by moderate southeasterly flow, increasing overnight cloud cover, and dew points supporting limited radiational cooling. This aligns with current spring conditions in the Southern Hemisphere, where September averages around 12°C but recent patterns have trended warmer. Trader sentiment remains closely split, with the 25°C-or-higher and 15°C-or-below bins reflecting uncertainty over exact steering patterns and any late-model shifts in boundary-layer moisture. Key resolution hinges on official station readings at resolution time, with potential for 1–2°C variance from mesoscale effects like urban heat or localized fog. Updated model runs and NHC-style regional guidance over the next 48 hours will likely tighten the distribution.