Current forecasts from major models indicate a minimum temperature near 19°C in Tokyo on May 19, driven by clear to partly cloudy skies under a weakening high-pressure ridge that permits moderate radiative cooling overnight. Light southerly winds and moderate humidity levels near 60-70% will limit further temperature drops, while the urban heat island effect in central districts adds roughly 1-2°C to baseline readings compared to rural outskirts. Recent shifts in the GFS and ECMWF runs have narrowed the spread, with slight cloud increases or wind speed variations of 2-3 m/s potentially tipping the low between 18°C and 20°C. These conditions align with typical mid-May climatology for the region, where stable spring transitions rarely produce extremes beyond the 15-22°C range.