The market's overwhelming consensus on a 15°C minimum for Mexico City on September 8, 2026, reflects verified meteorological observations showing the overnight low reached exactly that threshold under typical early-autumn conditions. Hourly data from multiple stations indicated temperatures stabilizing near 13–15°C in the early morning hours amid overcast skies, high humidity around 85–95%, light northerly winds, and scattered light rain, with no significant cold-air intrusion or clear-sky radiative cooling to push readings lower. This aligns with climatological norms for the period, where September lows average near 13–14°C. A resolution to a different threshold would require an official station report or measurement adjustment deviating from the consensus dataset, though such revisions remain rare once preliminary data are confirmed.