Recent numerical weather prediction models from sources including the Met Office and local Turkish meteorological agencies indicate a stable high-pressure pattern over the eastern Mediterranean, supporting a daytime maximum near 27°C for Istanbul on August 21 under mostly sunny skies with light northerly winds. This aligns with late-August climatology, where average highs range 27–29°C and daily variability typically stays within 2–3°C absent major frontal systems or heat advection. Trader consensus clusters on 26–28°C outcomes, reflecting agreement across ensemble runs while acknowledging minor spread from boundary-layer moisture and urban heat-island effects; no significant model shifts have occurred in the past 48 hours to alter these probabilities. Updated short-range forecasts expected over the next day will provide the final resolution inputs.