Recent forecast models from sources like GFS and ICON-EU indicate Istanbul's minimum temperature on September 26 will likely fall between 17–20°C, driven by northeasterly winds of 10–15 mph moderating overnight radiative cooling under partly cloudy skies. This consensus underpins the near-even market split between sub-13°C and 23°C+ outcomes, highlighting trader uncertainty around exact cloud cover and wind persistence that could shift the low by a few degrees. Historical September norms near 17°C provide context, while upcoming evening model runs from NOAA and local agencies may refine these projections ahead of market resolution.