Forecast models from agencies and meteorological services indicate a minimum temperature near 17°C for São Paulo on September 26, driven by clear skies, light easterly winds, and stable high-pressure conditions that limit nocturnal cooling. Recent observations show overnight lows of 16–18°C over the prior 48 hours, with dew points around 15–17°C supporting gradual radiational cooling under low cloud cover. This aligns with late-September climatology, though current readings run several degrees above the long-term average minimum of 12°C due to persistent warmth. Model consensus points to 17°C as the most probable low, while slight variations in boundary-layer moisture or wind could shift the outcome by 1°C. Updated short-range guidance expected overnight will refine resolution criteria for this 24-hour period.