Recent forecasts for Mexico City point to overnight lows near 13–14°C on October 12 amid widespread cloud cover, light rain, and high humidity from the ongoing rainy season, yet the 47% market-implied probability on 8°C or below reflects notable model uncertainty at the city’s 2,240-meter elevation. Persistent tropical moisture and variable steering patterns can produce sharper radiational cooling under clearing skies than ensemble averages suggest, while historical October minima often dip several degrees below daily guidance. Key upcoming inputs include refined National Meteorological Service of Mexico runs and final observational data that will resolve the precise minimum temperature threshold.