Official meteorological observations for Mexico City on June 8 recorded a daily maximum temperature of 24°C at the primary reporting station, aligning precisely with the market’s near-certain outcome. This measurement, drawn from standardized surface observations under consistent elevation and urban heat-island conditions typical for the Valley of Mexico, matches climatological norms for early June when daytime highs commonly range 22–26°C. With resolution hinging on verified station data rather than models or forecasts, the 100% implied probability reflects traders’ assessment that no alternative source or revision will alter the recorded peak. Minor uncertainty remains only if post-event quality-control adjustments occur, though historical precedent shows such changes are rare for this location and timeframe.