Current forecasts for Karachi on September 22 project an overnight low near 27–28°C under clear to mostly clear skies and moderate westerly winds, consistent with late-September climatology where coastal sea breezes and high humidity limit radiative cooling. Primary uncertainty stems from variable Arabian Sea moisture, wind speed fluctuations that could enhance or suppress the urban heat island effect, and minor model differences in cloud cover or dew-point depression. These factors explain the tight market spread between 23°C-or-below and 27°C outcomes versus higher bins, as even small shifts in steering patterns or boundary-layer mixing can alter the daily minimum by 2–3°C. Updated model runs and local observations in the next 48 hours will likely narrow the implied probabilities.