Japan Meteorological Agency forecasts confirm Tokyo's highest temperature on April 1 at 17°C, driving the 99.4% market-implied probability as cloudy skies and scattered rain from a low-pressure front suppress solar heating and daytime warming. Current observations align closely with this, matching the seasonal normal maximum of 16.9°C amid mild southerly flows but persistent overcast conditions that limit insolation. Model ensembles from JMA's numerical weather prediction systems show tight agreement around this value, reflecting stable spring patterns post-cherry blossom peak. Realistic challenges include unexpected clearing before afternoon peak heating, potentially pushing to 18°C via enhanced shortwave radiation, though hourly JMA updates and end-of-day station measurements at Tokyo observatory will clarify resolution.