Recent numerical weather prediction models, including consensus from GFS and ECMWF runs, indicate Mexico City overnight lows on September 2 will likely settle near 13°C, consistent with the city's 2,240 m elevation and typical early-September radiative cooling under partly cloudy, moist conditions with scattered showers. This range aligns with climatological September minima around 13°C, where dew points near 12–14°C and light winds limit further drops despite high relative humidity. The tight clustering of market-implied odds between 11–14°C reflects genuine forecast uncertainty from variable cloud cover and urban heat island effects, rather than any anomalous cold surge or heatwave. Updated model guidance over the next 24–48 hours, particularly on precipitation timing and boundary-layer mixing, will be the key catalyst for shifts in trader positioning before resolution.