In the United States, V-J Day is commonly observed as August 14, 1945, the date Japan’s surrender announcement was received and publicized in the Americas.
Japan’s announcement was made on August 15 according to Japanese calendar time. Because of the international date line and time-zone differences, it was still August 14 in much of the United States when the news was broadcast. This explains why both August 14 and August 15 appear in historical accounts.
The term can also refer to September 2, 1945, when Japanese representatives formally signed the Instrument of Surrender aboard USS Missouri. That ceremony legally completed the surrender process, while the earlier announcement triggered worldwide celebrations. V-J Day should therefore be understood as a date with different regional conventions rather than a single universally used calendar date.