**Trader sentiment for Mexico City's September 14 lowest temperature remains tightly balanced between 13°C and 14°C (roughly 48–53% implied probability each), reflecting genuine uncertainty in overnight minimums.** Pre-dawn forecasts from Mexico’s Servicio Meteorológico Nacional highlighted a minimum range of 13–15°C under partly cloudy skies with scattered showers and thunderstorms, which limited radiative cooling. Hourly observations near Benito Juárez International Airport and central stations showed temperatures bottoming near 13°C in the early morning hours before rising with daytime heating and humidity. Differentiating factors between 13°C and 14°C include subtle variations in cloud cover timing, localized rain-cooled air, wind speed, and the precise urban measurement site, all of which can shift the recorded low by 1°C. Historical September baselines for the city center hover around 10–12°C, but recent wetter, cloudier conditions elevated the floor. Market resolution will hinge on the final official SMN or airport reading once fully processed.