Persistent northerly winds and widespread showers across Istanbul on October 15, 2026, have suppressed daytime warming, with official station observations and forecast models from sources like the Turkish State Meteorological Service showing a maximum of 15–17°C under overcast skies and 10–25 m/s gusts. This setup aligns with mid-October climatology for the region, where cool maritime air from the Black Sea limits peaks near the seasonal average of 18–20°C. Recent model runs and hourly data confirm 15°C as the consensus high, driving the 79% implied probability, while lighter 16°C odds reflect residual uncertainty in localized clearing or brief sun. Updated observations through midday continue to anchor trader consensus around these thresholds.