Recent forecast models from agencies tracking Mexico City’s high-elevation subtropical highland climate point to overnight lows near 12–14 °C on September 20, driven by moderate northerly flow, increasing cloud cover, and scattered showers that limit radiative cooling after sunset. These conditions, typical for late wet-season nights at 2,240 m elevation, keep minimum temperatures well above the coldest historical analogs while still allowing modest drops if skies clear briefly around dawn. Market-implied odds remain tightly clustered across the 11–16 °C range because small differences in timing of precipitation or wind shifts can shift the daily minimum by 1–2 °C, creating genuine scientific uncertainty that traders price with real capital. Updated model runs and official station observations expected later today will clarify whether the low settles near the middle of the distribution or edges lower under clearer skies.