Trader consensus on Polymarket has converged to a 100% implied probability for Shanghai's highest temperature reaching exactly 29°C on May 11, 2026, anchored by official hourly observations from the resolution source—Shanghai Pudong International Airport meteorological station—which recorded a midday peak of 29°C under partly cloudy skies and light southeasterly winds below 12 km/h. Short-range numerical weather prediction models from the China Meteorological Administration and global ensembles like ECMWF aligned with this outcome, projecting highs in the upper 20s°C amid moderate humidity and stable high-pressure influence typical for early May in the Yangtze River Delta. While temperatures have since trended downward into the evening, a realistic challenge would require an improbable late-afternoon heat burst from enhanced solar insolation or sudden wind shift, with final daily maximum data expected from official reports within 24 hours.