Trader consensus has converged on 19°C as Shanghai’s lowest temperature on May 16, reflecting official forecasts from the China Meteorological Administration and ensemble guidance showing stable high-pressure conditions with light winds and minimal cold-air advection. These factors produced typical radiative cooling under clear skies, anchoring the overnight minimum near the mid-May climatological average of 18–20°C. Verified surface observations from local monitoring networks align closely with this outcome, leaving narrow model spread. Resolution hinges on precise station data thresholds, so an unforecasted enhancement in nocturnal cooling remains the primary scenario that could realistically produce an 18°C reading or lower.