What time was the Hiroshima bomb dropped? 6 August 1945, 08:15 local time

Short answer: the atomic bomb exploded over Hiroshima at 08:15 on 6 August 1945, Japan time. Japan is nine hours ahead of UTC, so in UTC the same minute is 23:15 on 5 August 1945.

The morning

The B-29 Enola Gay, flown by Colonel Paul Tibbets, took off from Tinian in the Mariana Islands in the early hours. The weather over Hiroshima was clear. The bomb, known as Little Boy, was released and fell for under a minute before detonating in the air above the city.

08:15

Stopped watches found in the ruins, some now in the Hiroshima Peace Memorial Museum, show the time. The city marks the minute every year: at 08:15 on 6 August, the peace bell rings and the city falls silent. Tens of thousands of people were killed instantly, and many more died by the end of the year from injuries and radiation.

Why the date is different in UTC

The event happened on the morning of 6 August in Japan. In London it was still the evening of 5 August, and in Washington it was early evening on 5 August. Any record fixed to a single global clock has to choose. In UTC, the minute is 23:15 on 5 August.

Sources

• Encyclopaedia Britannica: Atomic bombings of Hiroshima and Nagasaki
• Hiroshima Peace Memorial Museum

Some minutes should belong to nobody. See the museum for the minutes held as archive records.