Current ensemble forecasts from global models point to a stable high-pressure regime over central Mexico, supporting a daily maximum near 22–23 °C in Mexico City on September 17. Light winds, modest afternoon mixing, and only isolated showers limit upward temperature spikes, while the city’s 2,240 m elevation and typical September moisture keep readings below seasonal peaks. Minor differences among model runs—primarily in cloud timing and boundary-layer depth—create the narrow spread between 23 °C and 24 °C outcomes, with lower probabilities assigned to 25 °C or higher due to the absence of strong subsidence or clear-sky reinforcement. Updated runs closer to the date will refine these thresholds.