Why do people hang futons and laundry outside so often?
On sunny days you'll see futons draped over balconies and railings, and laundry line-dried outdoors, even in cities. People beat the futons and bring everything in before evening.
Sun and air dry out humidity, kill mites and odors, and freshen bedding in a warm, damp climate where dryers were long uncommon.
Why — five layers
Japan's humid summers and rainy season make mold and dust mites a real problem, so airing and sunlight are practical defenses for futons that sit on the floor.
Sun-dried bedding is felt to be genuinely clean and pleasant (that warm 'sun smell'), tying into the broader value placed on freshness and cleanliness.
Clothes dryers were long rare and energy is expensive, so line-drying and futon-airing remained the default even where dryers now exist (mottainai—don't waste).
International view
Line-drying laundry is common worldwide, but routinely airing thick futons over balcony railings is distinctively tied to floor-sleeping households in Japan and nearby regions.
But not always
Many buildings ban visible balcony drying for looks or safety, so residents use indoor racks or futon dryers instead. Beds and duvets are also increasingly common, especially among younger urban people.
What to do
Check your building's rules before hanging futons over the railing. If airing, do it midday on a dry day and bring bedding in before the evening damp returns.
Sources
- Resident testimony; general accounts of Japanese bedding and climate