**Recent meteorological observations and forecast models for São Paulo on October 1, 2026, show the daily maximum stabilizing near 26°C under persistent cloud cover and scattered rain tied to a frontal boundary and upper-level trough.** These conditions limit solar heating and align with multiple agency runs projecting afternoon peaks in the mid-20s Celsius, slightly above the early-October climatological average. Real-time data from stations indicate morning readings climbing into the mid-20s before stabilization, supporting the strong market-implied odds for 26°C. A faster-than-expected clearing of clouds or weaker precipitation could allow brief additional warming toward 27–28°C, while heavier or more prolonged rain might hold the high at 25°C or below.