Recent forecasts from multiple models indicate Istanbul's overnight low on September 27 will likely fall between 16–19°C amid increasing northeasterly winds and scattered showers associated with an approaching frontal system. Ensemble guidance shows modest cooling from current conditions near 19°C, with precipitation timing and cloud cover introducing variability in the exact minimum. This uncertainty—typical of short-range model spread in transitional autumn patterns—supports the near-even market split between sub-13°C and 23°C+ outcomes, while centering probability on mid-range values around 17–18°C. Updated model runs and official Turkish meteorological guidance in the next 24–48 hours will likely refine these ranges ahead of market resolution.