Koromogae Day: Seasonal Wardrobe Switch (Koromogae no Hi)

What Is Koromogae no Hi?

June 1st is "Koromogae no Hi" — the day of "koromogae," the custom of switching one's clothing from winter wear to summer wear (and vice versa) with the change of seasons. Many schools and workplaces switch their uniforms to summer styles on June 1st and back to winter styles on October 1st, making koromogae one of the seasonal traditions that mark the rhythm of the year in Japan.

The Origins and History of Koromogae

The roots of koromogae trace back to a Heian-era (794–1185) court ritual called "koi," itself adapted from a Chinese imperial custom. Switching between summer and winter clothing allowed people to enjoy the fashions of each season while also helping manage their health.

• Heian Period: The imperial court practiced "koi," switching clothing on April 1st and October 1st (by the old lunar calendar).
• Kamakura to Muromachi Periods: The custom spread to samurai society, with clothing changes occurring two to four times a year.
• Edo Period: A schedule of four changes per year — on the 1st day of the 4th month, the 5th day of the 5th month, the 1st day of the 9th month, and the 1st day of the 10th month (all by the lunar calendar) — became standard and spread to ordinary people as well.
• Meiji Period: With the adoption of the modern solar calendar, the government, military, and schools officially designated June 1st and October 1st as the koromogae days — the direct root of today's practice.
• Today: Partly due to the effects of climate change, the timing of koromogae has become more flexible, varying by individual and region.

Koromogae Was a Major Event in the Edo Period

In the Edo period, koromogae held special significance for ordinary townspeople. Those without much money would pawn off-season clothing at a pawnshop and redeem it when the season changed — a practice known as "shichiire koromogae" (pawnshop wardrobe switching). On koromogae day, the streets would buzz with activity as everyone swapped their clothing at once.

Modern Koromogae: When and What to Switch

Today, koromogae is mainly done according to personal comfort and local climate, but here are some general guidelines.

• Switching to Summer Clothes (late May to early June): Short-sleeved shirts, lightweight tops, linen fabrics, etc. A good rule of thumb is once daytime highs consistently exceed 25°C (77°F).
• Switching to Winter Clothes (October to November): Sweaters, coats, fleece, etc. A good rule of thumb is once nighttime lows drop below 15°C (59°F).
• Transitional Seasons (Spring and Fall): Long-sleeved T-shirts, light cardigans, trench coats — layer pieces that can be adjusted as temperatures fluctuate.

Tips for Koromogae and Storing Clothes

• Wash Before Storing: Storing clothes with leftover dirt or body oils can cause discoloration, moth damage, or mold. Always wash or dry-clean items before putting them away.
• Use Mothballs/Repellent: Wool, cashmere, and silk are especially vulnerable to moth damage. Since repellent vapors sink downward, place mothballs on top of stored clothing for best protection.
• Use Vacuum Storage Bags: Bulky items like down jackets, blankets, and sweaters take up much less space when compressed in vacuum storage bags.
• A Chance to Declutter: Koromogae is the perfect opportunity to let go of anything you haven't worn in over a year. Sorting through your wardrobe keeps your closet organized and manageable.
• Guard Against Humidity: Place moisture absorbers in storage areas to prevent mold during Japan's rainy season (tsuyu).

Fun Facts About Koromogae

• The word "koromogae" is sometimes translated into English as "changing of clothes" or "seasonal wardrobe change."
• In Okinawa and the Amami Islands, koromogae often takes place a month earlier than on the Japanese mainland, on May 1st.
• The Japanese word for "changing room" (　更衣室, "koi-shitsu") literally means "a room for renewing one's clothing," reflecting its deep ties to the koromogae tradition.
• Japan's distinctly four-season climate and the culture of koromogae are closely intertwined — and this connection lies behind business concepts like Uniqlo's "LifeWear," which designs clothing for seasonal transitions.

How to Spend Koromogae Day

• Carefully wash or dry-clean your winter clothes before storing them, so they're ready to wear comfortably again next season.
• Use koromogae as a chance to sell or donate anything you haven't worn in over a year via secondhand shops or resale apps, decluttering your closet.
• Check your summer clothes, make a list of anything worn out or outdated, and plan replacements thoughtfully.
• Replace mothballs and moisture absorbers with fresh ones to prepare your storage space for the rainy season ahead.

Dressing for the Season: An Expression of Japanese Sensibility

Koromogae Day on June 1st is about more than just switching clothes — it's a uniquely Japanese way of living that involves sensing the change of seasons with all five senses and using that awareness to reorganize daily life. As you slip into your summer clothes for the first time, take a moment to feel the refreshing sense of a new season beginning.