Recent short-range forecasts from the China Meteorological Administration and global models indicate Shanghai’s overnight low on May 20 will likely settle near 20–22 °C under a persistent high-pressure ridge that traps heat and limits radiative cooling at Pudong International Airport. This setup continues the mid-May warm anomaly observed in recent nights, where minima have exceeded the 16–18 °C climatological average for late spring. Light southeast winds below 12 km/h and increasing cloud cover further suppress temperature drops, elevating the market-implied odds for readings of 22 °C or higher. Updated model runs through the next 48 hours will refine the exact threshold, while any late clearing could allow modest cooling toward 19 °C.