Climatological norms for Tokyo in late April demonstrate mean daily maximums consistently above 15°C. JMA historical data for April 27 over the last five years averages 22.2°C, with the lowest recorded high at 20°C. This robust empirical evidence indicates the 15°C threshold is remarkably low for the period, strongly biasing toward a 'yes' resolution. Barring extreme cold air advection or an unseasonal anticyclonic block, breaching 15°C is a near certainty. [95]% YES — invalid if a major, unforecasted polar front brings exceptional cold to the Kanto plain.
