Forecast models from agencies and meteorological services converge on a maximum temperature of 21°C for Warsaw on September 28, 2026, under clear skies, high pressure near 1030 hPa, and light southeasterly winds of 5–10 km/h. These stable anticyclonic conditions promote strong diurnal heating with minimal cloud cover and negligible precipitation risk, consistent with late-September climatology at 52°N latitude where average highs range 18–20°C. Real-time observations show afternoon readings climbing through 19–20°C, supporting the market’s heavy weighting toward 21°C while leaving limited room for 20°C or 22°C deviations if boundary-layer mixing or insolation varies slightly. Updated model runs through the day will refine the precise peak before official station data finalize the outcome.