Current forecasts from multiple models, including GFS and ensemble guidance, indicate Istanbul will experience mostly clear skies with northeasterly flow on September 10, supporting daytime highs near 27–28°C and overnight lows of 18–21°C under stable high pressure. This places the expected minimum in a narrow band around 20°C, consistent with seasonal norms but slightly above the long-term September average low of 17°C. Trader sentiment remains closely split between outcomes above 27°C and 17°C or below because small shifts in wind speed, cloud cover, or the timing of any subtle cold-air advection could alter nocturnal radiational cooling rates by several degrees. Upcoming model runs and surface observations over the next 48 hours will likely resolve the primary uncertainty in boundary-layer conditions.