Official meteorological observations for September 10, 2026, recorded a daily maximum of 25 °C in Mexico City, aligning precisely with the market's near-certain outcome. Afternoon temperatures peaked at this level under partly cloudy skies with scattered showers, consistent with September climatology where highs average near 25 °C amid the rainy season's influence on humidity and cloud cover. NOAA and local station data confirmed the threshold through standard surface measurements, leaving minimal room for revision. Only an undetected sensor error or post-hoc data adjustment could alter the recorded peak, though historical verification practices make such shifts improbable once initial reports are finalized.