Recent forecasts for Mexico City on September 15 point to a maximum near 22–24°C under mostly overcast skies with light rain possible, aligning with the closely matched market probabilities for 23–25°C. At 2,240 meters elevation, the city’s highland location caps daytime heating even in late summer, while the ongoing rainy season brings persistent cloud cover and scattered precipitation that reduces solar insolation and limits afternoon temperature peaks. Model consensus shows modest variability tied to the exact timing and coverage of showers, which can suppress the daily high by 1–2°C when widespread. Historical September averages near 23–24°C provide context, but short-term shifts in steering patterns or moisture could nudge the observed maximum across the 23–25°C thresholds that dominate trader positioning. Updated model runs and official observations in the next 48 hours will likely refine these odds.