Traders have converged on a 22°C high for Warsaw on June 17 because multiple numerical weather prediction models, including ECMWF and GFS runs, consistently forecast peak surface temperatures near that value under a stable high-pressure ridge with moderate westerly flow, limited cloud cover, and daytime insolation producing a maximum around 21–23°C. Official observations from Polish meteorological stations align with this consensus through the afternoon hours, leaving little room for deviation as the diurnal temperature cycle nears its end. Realistic challenges include unforecasted convective cloud development suppressing the peak by 1–2°C, a late warm-air advection spike, or station-specific microclimate effects that could shift the recorded maximum outside the narrow 22°C bin.