**Trader consensus has converged on 28°C as the highest temperature recorded in São Paulo on September 11, 2026, with near-certain implied probability.** This positioning reflects post-event verification through official meteorological observations, primarily from stations such as those operated by Brazil’s National Institute of Meteorology (INMET) or equivalent airport data (e.g., Congonhas). Hourly records show daytime peaks reaching approximately 28–29°C under partly cloudy conditions with moderate humidity, consistent with typical early-spring patterns in the region where maximums average around 24–26°C but can vary with synoptic influences like high-pressure systems suppressing cloud cover and allowing greater solar heating. Uncertainties that could alter resolution include minor discrepancies between reporting stations, rounding conventions to the nearest degree, or revisions in preliminary versus final datasets, though the tight clustering around 28°C indicates strong agreement in verified measurements.