Here is a gist of all the major Hiroshima events and festivals:

• Oyster Festival: The harvest season for oysters is generally between February to March. If you love oysters, the festival is celebrated with fun events held at various locations across the Hiroshima prefecture.
• August 6th: If you are in Hiroshima on August 6th, you will witness events dedicated to the memory of the World War II atomic bomb attack. At the Peace Memorial Park, at 8:15 am, the Peace Bell is rung and sirens go off throughout the city, followed by a minute of silence for the people who died.
• Hiroshima Food Festival: Usually held in the month of October, local dishes from across the Hiroshima prefecture are available at one place during this two-day celebration of Hiroshima's culinary treasures.
• Apart from these, other events and festivals include the Hiroshima Dreamination, Yukata Festival, Emperor’s Birthday and Culture Day.