The United States observed V-J Day on August 14, 1945, after Japan announced its surrender.
President Harry S. Truman announced Japan’s acceptance of the Allied surrender terms on the evening of August 14 in Washington, D.C. Because of time-zone differences, the news reached Japan on August 15, which is the date commonly commemorated there as the end of the war. Many other Allied countries also marked August 15 as V-J Day.
The announcement followed Japan’s decision to accept the Potsdam Declaration, which had demanded the unconditional surrender of Japanese armed forces. Emperor Hirohito recorded a radio address explaining the decision, and it was broadcast to the Japanese public on August 15. The formal legal surrender did not occur until September 2, when Japanese representatives signed the surrender instrument aboard USS Missouri in Tokyo Bay.
This creates a common date mix-up: August 14 is the main U.S. observance, August 15 is the Japanese broadcast date, and September 2 is the date of the formal signing.