Official Japan Meteorological Agency (JMA) observations from Tokyo's primary stations, including Haneda, recorded an early morning low of 13°C around 4-6 a.m. JST on April 28, aligning with the diurnal temperature minimum typical for late April under partly cloudy skies and light southerly winds. This matches yesterday's JMA forecast update and model consensus from GFS/ECMWF runs, which projected mild overnight conditions amid a broader spring warming trend, with historical April lows averaging 10-12°C but this day skewed higher due to persistent high pressure. Trader consensus at near-certainty reflects these verified measurements, as daytime temperatures have since risen above 20°C. Realistic challenges include rare post-dawn dips from unexpected clear skies or data revisions from secondary stations, though JMA final daily summaries—expected later today—rarely alter early lows.