Forecast models from the Turkish State Meteorological Service and international agencies indicate Istanbul will reach a daily maximum of 24–26°C on October 11 amid a warm “pastırma yazı” spell, well above the seasonal average near 20°C, with light southerly winds, mostly cloudy skies, and negligible precipitation. Trader consensus has priced 27°C as the leading outcome at 49.5% implied probability, followed by 26°C at 30%, reflecting slight upward bias in some ensemble runs or potential for localized urban heat effects to push readings marginally higher before the front arrives. Resolution will hinge on the official highest recorded value at authorized stations, with any late-day clearing or measurement revisions capable of shifting the final tally within the narrow 26–28°C band that dominates current market-implied odds.