During summer events such as fireworks displays and festivals, many Japanese wear lightweight summer kimonos called yukata that are much easier to put on than formal kimonos.
 
Yukata were originally hemp kimonos worn by nobles for bathing. During the Edo era, however, public baths became popular and people from all walks of life started wearing yukata as bathrobes. They gradually evolved into outdoor garments with ornate patterns and are now considered quite fashionable.

Yukata continue to be worn at onsen (hot springs), because they keep wearers cool and absorb their perspiration. They are also commonly worn as indoor clothing at ryokan (inns).
 
If you thought onsen were only for the winter, we recommend trying a breezy open-air onsen (rotenburo) in the summer. At Hakone Kowakien Ten-yu, which opened in April only two hours from Tokyo, you can enjoy an indoor onsen with views of waterfalls and greenery or an "infinity hot spring" rotenburo that seems to float in the sky with an impressive unobstructed view of the surrounding scenery. Of course, yukata are ready and waiting when you step from the hot water.

■Hakone Kowakien Ten-yu
For details, visit: http://www.hakone-tenyu.com/