Trader sentiment for Istanbul's August 21 minimum temperature clusters tightly around 21–23°C because long-range models and climatological baselines show typical overnight lows of 20–22°C under seasonal high pressure and moderate northeasterly flow from the Black Sea. Clear to partly cloudy skies allow moderate radiative cooling after sunset, while the urban heat island and Bosphorus moisture limit further drops below 19°C. Recent forecast runs from agencies such as the Turkish State Meteorological Service and ECMWF indicate minimal day-to-day variability, with no strong cold advection or cloud cover expected to push readings lower. The narrow spread among the 20–23°C bins reflects remaining uncertainty in exact pre-dawn timing, wind speed, and which official station (Atatürk Airport versus city-center sites) supplies the resolving measurement, rather than any major shift in atmospheric conditions. Higher outcomes remain negligible given the established August average low near 20°C and absence of anomalous cooling signals.