Trader sentiment in the Tokyo temperature market reflects a narrow split between 28°C and 29°C because the latest Japan Meteorological Agency model runs project an afternoon high in that range under a weak high-pressure ridge and partly cloudy skies. Sea breezes from Tokyo Bay are expected to moderate peak heating, while recent upper-level warming has lifted baseline May values above the long-term average of 23°C. Ensemble guidance shows only modest support for 30°C or higher, contingent on stronger insolation or delayed cloud cover, with the 22.5% probability for that outcome tied to typical forecast uncertainty in springtime boundary-layer mixing. Updated surface observations through the evening will determine the final maximum and resolve the closely matched leading probabilities.