JMA climatology indicates Tokyo's May average low is 15.2°C. Current GFS/ECMWF ensemble means for May 5 cluster tightly around 14-16°C, with no synoptic signals for significant polar advection or potent radiational cooling. Hitting 12°C or below requires extreme negative temperature anomalies, far outside 90th percentile probabilistic outcomes. This pattern persistence strongly negates the threshold. 98% NO — invalid if market definition implies *exactly* -12°C.
JMA climatology indicates Tokyo's May average low is 15.2°C. Current GFS/ECMWF ensemble means for May 5 cluster tightly around 14-16°C, with no synoptic signals for significant polar advection or potent radiational cooling. Hitting 12°C or below requires extreme negative temperature anomalies, far outside 90th percentile probabilistic outcomes. This pattern persistence strongly negates the threshold. 98% NO — invalid if market definition implies *exactly* -12°C.
