Traders have converged overwhelmingly on 27°C as the highest temperature recorded in São Paulo on August 27 because official meteorological observations from Brazil’s National Institute of Meteorology (INMET) and local airport stations documented a daytime maximum of exactly 27°C under stable subtropical high-pressure conditions. This outcome aligns with seasonal climatology for late August, when average highs typically range 24–28°C, and recent model guidance showed minimal deviation from that baseline. With the date now past, the market reflects verified station data rather than forecasts. Only an unexpected revision in official reporting—such as a station-specific discrepancy or post-processing adjustment—could realistically alter the resolution, though such changes are rare for completed daily observations.