Recent ensemble forecasts from European and GFS models indicate a high near 19–20 °C in Warsaw on August 18, driven by westerly flow advecting cooler maritime air masses that increase cloud cover and support early showers. These conditions reduce surface insolation and limit boundary-layer mixing, suppressing afternoon temperatures below the seasonal average of 23–26 °C. Trader sentiment clusters tightly around the 19 °C and 20 °C outcomes because small shifts in frontal timing or cloud persistence can alter peak values by 1–2 °C. Short-range model updates and real-time observations on the 18th will refine the exact maximum, highlighting the inherent uncertainty in convective and radiative processes for this timeframe.