**Trader sentiment for the lowest temperature in Mexico City on September 7, 2026, centers overwhelmingly on 14°C (53% implied probability), reflecting pre-event forecasts and overnight observations from official sources like CONAGUA and the Servicio Meteorológico Nacional.** Mexico City’s high elevation (~2,240 m) typically produces moderate nighttime lows, but September’s rainy season brings persistent cloud cover (often 80–100%) that limits radiative cooling and keeps minimum temperatures in the 13–15°C range. Hourly data showed readings holding near 13–14°C through the early morning hours amid light rain or showers and high humidity (70–95%), with no strong cold-air advection or clear-sky conditions to drive sharper drops. Forecasts issued the day prior consistently projected a daily minimum near 14.4°C, aligning with climatological September averages (around 10–13°C lows but elevated by moisture and clouds). The 13°C outcome carried only marginal probability because models showed limited downside risk from additional cooling. Lower thresholds (12°C or below) remained near zero as historical analogs and current steering patterns offered no support for significant departures. Post-event data reinforced 14°C as the resolution point, consistent with the market’s heavy weighting.