This festival is famous for being all about the yukata (a cotton summer kimono).
It marks the beginning of the season of wearing yukatas. There are bon dances, and various outdoor stalls of foods and games.
First Friday-Sunday weekend of June
Address: 8-12 Mikawacho Naka Ward, Hiroshima, 730-0029 (Enryuji Temple)
http://www.hiroshima-navi.or.jp/en/event/398130.php (Official site)