Trader consensus on Polymarket has locked in a 100% implied probability for a highest temperature of exactly 30°C in Sao Paulo on March 25, driven by official observations from Brazil's National Institute of Meteorology (INMET) confirming this precise peak reading at key weather stations like Congonhas and Mirante de Santana. Mild autumn conditions prevailed, with partly cloudy skies, light southerly winds, and no significant heat advection, aligning with pre-event forecast model consensus from GFS and ECMWF that projected highs in the upper 20s to low 30s Celsius. Historical March averages for Sao Paulo hover around 27–29°C, making 30°C a plausible but unremarkable outcome. Realistic challenges would require rare post hoc data revisions from INMET audits or disputes over measurement site validity, though such events are exceedingly uncommon for settled daily records.