Recent ensemble forecasts from ECMWF and GFS models indicate Istanbul’s August 29 maximum will likely peak between 24–27 °C under partly cloudy skies with a 30–50 % chance of brief showers and moderate northerly flow. This tight clustering around 25 °C explains the near-even market split between the 24 °C and 25 °C outcomes, as small shifts in cloud cover, timing of any precipitation, or boundary-layer mixing can alter the daily high by 1–2 °C. Historical late-August climatology supports similar values, while the absence of strong warm-air advection or subsidence keeps probabilities for 27 °C or higher below 10 %. Updated model runs and official Turkish Meteorological Service guidance in the next 24–48 hours remain the key variables that could refine these market-implied odds.