Trader consensus has settled on 16°C as the verified daily maximum temperature in Sao Paulo on September 13, anchored by official post-event meteorological observations from Brazilian weather authorities. Ground-station measurements eliminate forecast uncertainty and directly inform resolution criteria, producing near-certain market-implied odds. September climatology in the region typically features daytime highs between roughly 15–22°C, placing this reading within expected seasonal variability without notable extremes. Minor data discrepancies across stations remain possible but are uncommon in established networks, while any measurement revisions would need to be substantial to shift the recorded peak.