Recent ensemble forecasts from the European Centre for Medium-Range Weather Forecasts and Global Forecast System indicate Istanbul’s May 19 peak will likely settle near the mid-May climatological average of 20–22 °C, driven by moderate southeasterly flow and limited moisture that favors 21–22 °C outcomes. Traders weigh these model runs against historical Turkish State Meteorological Service records, where sea-breeze suppression from the Marmara often caps afternoon heating by 1–2 °C while variable cloud cover introduces minor spread across runs. This scientific uncertainty keeps the 22 °C and 21 °C brackets closely matched, with lower probabilities assigned to outliers beyond 23 °C absent stronger warm advection. Updated model guidance and any shifts in boundary-layer moisture ahead of the date remain the key variables that could refine market-implied odds before official station observations resolve the market.