**Trader sentiment for the lowest temperature in Mexico City on September 2, 2026, reflects substantial forecast uncertainty, with multiple outcomes (notably 11°C, 13°C, 14°C, and 15°C) clustered near 50% implied probability.** This balance stems from the city's high-elevation basin setting (~2,240 m), where strong diurnal temperature swings are common, especially during the late rainy season when average nighttime lows hover around 11–14°C. Key drivers include variable cloud cover, precipitation timing, and radiative cooling rates. Clear or partly cloudy conditions overnight enhance longwave radiation loss from the surface, favoring cooler minima near or below 12°C. Persistent cloudiness or showers—common in early September—trap heat and raise minimums toward 14–15°C by limiting cooling. Current late-August patterns show frequent thunderstorms and high humidity, which may moderate temperatures if they linger, though any clearing trend could sharpen the drop. Ensemble model spreads and recent observational trends support this tight range rather than extremes, with 8°C or below remaining low-probability given seasonal baselines and limited cold-air advection potential. Upcoming model runs closer to the date will likely refine the exact minimum by clarifying overnight stability and moisture.