Recent global forecast models from major centers converge on a Shanghai overnight low of 19–21°C for May 19, 2026, with ensemble spreads reflecting modest uncertainty from variable cloud cover and light northeasterly flow. Late-spring climatology places the long-term median minimum near 18°C, but a transient moisture surge and associated rainfall expected Tuesday night could suppress radiative cooling just enough to hold temperatures above that baseline. Surface pressure gradients remain weak, limiting advection of cooler air, while urban heat-island effects add roughly 1°C to official Pudong readings. Traders therefore assign the highest implied probabilities to the 19°C, 20°C, and 21°C outcomes, with resolution hinging on the final 00 UTC model run and any last-minute adjustments to dew-point forecasts.