Traders have aligned on 22°C as São Paulo’s lowest temperature for August 29, driven by verified surface observations from Brazil’s National Institute of Meteorology (INMET) and automated weather stations confirming this exact minimum under stable high-pressure conditions. Late-winter climatology for the region typically produces overnight lows in the 15–20°C range, and the reported readings matched this pattern without notable cold-air intrusions or model discrepancies. The market-implied odds reflect this convergence of official data, leaving minimal uncertainty once final measurements are released. Only an unusual post-hoc correction to station records or redefinition of the measurement window could realistically shift the outcome.