Forecast consensus from multiple models points to a minimum near 13–14°C for Mexico City on September 26, reflecting the city’s 2,240 m elevation that promotes strong nocturnal cooling under typical late-September conditions. Persistent moisture from the rainy season, variable cloud cover, and light winds are limiting radiative heat loss while also preventing deeper drops, consistent with historical September lows averaging 10–14°C. Slight model differences in shower timing and boundary-layer mixing create the tight clustering around 13–15°C outcomes, while the near-even split between the 16°C-or-higher and 6°C-or-below bins captures remaining uncertainty in exact overnight minima ahead of final observational data.