Forecast models for Mexico City on August 19 project a daily maximum near 25–26°C, consistent with the closely matched market probabilities for those outcomes. At 2,240 m elevation, the city’s high-altitude subtropical highland climate keeps summer highs moderate even during peak insolation. The ongoing rainy season drives frequent afternoon convection and showers, which increase cloud cover, reduce surface heating, and often cap temperatures below clear-sky potential. Recent observations show patchy rain and highs in the low-to-mid 20s °C, aligning with climatological August averages of 24–25 °C. Minor model differences in timing or intensity of showers account for the tight spread between 25 °C, 26 °C, and 27 °C, with traders weighting the likelihood of brief clearing versus sustained cloud cover.