Eng 
日本語 
In Japan, the rather sudden change of seasons has lead to a very interesting custom called koromogae 「衣替え」: to change one’s wardrobe seasonally. The tradition began when all the people in certain regions of Japan changed their kimono from winter to summer’s style, then back again. Not only schools but companies and various institutions that have uniform would set a date on which everyone switch from summer clothes to winter clothes in October or the reverse in June. How many other culture would have a word for seasonal change of clothing?!
Koromogae is not only about changing from short sleeves to long sleeves, but it is also a change of colors and fabrics. The department stores and shops will completely renew their collection, accessories, patterns and design for each season.
Very often the date would be set on the 1st of October and the 1st of June. The funny detail about koromogae is that in the end the change of wardrobe is done regardless of the actual temperature and weather.
Sometimes, the weather is too hot to change to winter clothes or to cool to wear light clothes in June. For that reason, before the koromogae, there is a period called ikôkikan – period of transition, that would last one to two weeks, during which people are free to wear summer or winter clothes as they want. Another interesting fact is that before the time you change from winter clothes to summer clothes, you should take the outer garment of your coat to the dry cleaner.
Nowadays, only schools with uniform – called seifuku 「制服」- and companies having a very specific dress code are maintaining the tradition.
例：私は衣替えをします。
Example: I am going to change my clothes for the season.
例：6 月 1 日は衣替えの日です.
Example: We change into summer clothes on the first day of June.
Conversation examples korogomae for October :
Japanese
A: 明日、１０月１日だけど、衣替えしなくちゃいけないかな、まだ暑いよ・・・
B: 気温には関係ないよ、学校のルールだから、ブレザーを着ていかなきゃ。
English translation
A: Tomorrow is the first of October but would it be really impossible not to change my clothes (＊for winter) It is still hot…
B: Temperature has nothing to do with it, it your school’s rule, so you must wear your blazer.
A conversation example for korogomae in June:
