Official meteorological observations for Buenos Aires on August 28 recorded a maximum temperature of 21°C, establishing the market's near-certain consensus on that outcome. This reading, drawn from authoritative surface station data under standard World Meteorological Organization protocols, reflects typical late-winter conditions in the region with limited warm-air advection from the north. Traders' overwhelming positioning stems from the rapid availability of verified measurements once the calendar day closed, eliminating forecast uncertainty. While minor post-event quality-control revisions remain theoretically possible, historical records indicate such changes rarely shift daily maxima enough to affect resolution thresholds in this range.