Recent ensemble forecasts from the Met Office, GFS, and European models converge on a Warsaw high near 19–21 °C for August 18, driven by westerly flow advecting cooler maritime air, increasing cloud cover, and possible early showers that limit daytime heating and boundary-layer mixing. These conditions create tight uncertainty between 19 °C and 20 °C outcomes, as modest variations in cloud thickness or shower timing can shift the daily maximum by 1 °C. Historical August averages near 23 °C provide context, but current steering patterns favor suppressed temperatures relative to climatology. Updated model runs and official observations through the afternoon will refine the exact peak before market resolution.