Yukata Matsuri
Mid june, runs 2-3 days. locals criticize this festival for having no roots or real reason to exist other than an opportunity for girls to dress up in summer yukata, eat delicious food from booths, and play fair games. which is a good enough reason to go. this festival is always packed and makes for great people-watching, as many kinds of japanese subcultures are on display.
Cherry Blossom Viewing Party
Usually around the second sunday in april. lots of koto and taiko drumming.
Himeji Castle is particularly striking and crowded in cherry blossom season in April, when all the trees planted in and around the castle burst into white splendor.
Most people visit only the Castle and the area between the castle and the station. However, the area around the castle is a great place for a refreshing walk or a picnic. For families in particular, the park behind Himeji castle offers a decent play structure and ample space to sit down and have a picnic in the shadow of Japan's most famous castle.
Oshiro Matsuri
Early august. a large parade down the main street ending at himeji castle. there is also a big stage to see lots of dancing, which can range from either very traditional to very hip. often it's a combination of the two.
Himeji has a number of matsuri festivals throughout the year.
Moon viewing
In september near the time of the harvest moon. features traditional plays and drums.