**Trader consensus has converged on 20°C as the highest temperature recorded in Warsaw on September 10, 2026, driven by real-time observational data from official meteorological stations showing afternoon peaks reaching that exact threshold under overcast skies and light westerly winds.** Hourly readings indicate temperatures climbed steadily from morning lows near 16–17°C to a maximum of 20°C by midday and early afternoon before declining, consistent with regional patterns influenced by a stable high-pressure system and moderate humidity levels around 50–60%. This outcome aligns with verified surface observations rather than model projections, leaving minimal room for revision unless post-processing adjustments or alternative station data emerge. Upcoming official daily summaries from agencies like the Polish Institute of Meteorology and Water Management could provide final confirmation, though current measurements already support the market's strong positioning.