Trader consensus on Polymarket has locked in 11°C as the highest temperature at Warsaw Chopin Airport on April 28, 2026, with 100% implied probability, driven by IMGW and ECMWF ensemble forecast models converging on this peak amid persistent northerly winds advecting cool Arctic air masses. Morning observations registered 8°C under partly cloudy skies following overnight ground frost warnings (down to -8°C), while mid-afternoon readings hovered around 9-10°C with limited solar insolation due to variable cloud cover—well below April climatological averages of 13°C. This positioning reflects strong alignment between official observational data from the airport station (resolution source via Wunderground) and model guidance capping daytime heating. Realistic challenges include unexpected afternoon clearing enabling a brief 1°C surge via enhanced insolation, though persistent cool advection and overcast conditions render higher outcomes improbable; final IMGW hourly updates through evening will confirm the daily maximum.