The market's near-certain pricing on 18°C as the daily high in Buenos Aires on October 2 reflects official meteorological observations confirming that temperature as the peak reading from the central city station. With October marking the start of spring in the Southern Hemisphere, typical highs hover near 20°C, yet recent model guidance and surface data aligned closely with this value amid stable high pressure and light winds that limited afternoon warming. Traders priced in negligible probability of deviation because final daily summaries from the national weather service rarely undergo material revision after initial release. Only an extraordinary data correction or station-specific anomaly could shift the recorded maximum outside the 18°C bin.