Choosing by season — snow baths Dec–Mar, peak open-air Oct–Nov

The same bath is a different experience by season — and some only open part of the year.

Dec–Mar: snow bathing

Tsurunoyu, Sukayu, Manza, Nozawa, Jigokudani (monkeys). Heavy-snow years stop transport, so allow slack.

Apr–May: fresh green, reopenings

Zao's big open-air bath opens in late April. High-altitude baths are still cold outside — perfect for the tub.

Jun–Aug: summer

Seaside baths (Shirahama's Saki-no-Yu) extend hours in July–August. Highlands (Manza, Kusatsu) are cool. City super sento offer air-con and cold plunges.

Sep–Nov: autumn leaves, the best open-air season

Okuhida Hirayu, Kurokawa, Naruko, Iya. Air and water temperatures are in balance.

When to avoid

New Year, Golden Week and Obon mean crowds and surcharges (Manza, for one). Ryokan often suspend day-use bathing.