How hot and humid does Japan get in summer?

July and August reach the mid-30s °C in the cities, and the humidity makes it feel hotter still. Heat advisories are common and worth respecting. Plan the way locals do: sightseeing early, indoors between about eleven and three, then out again in the late afternoon and evening. Hokkaido and the mountain resorts are several degrees cooler if you want to sidestep it entirely.

When is the rainy season, and will it ruin a trip?

Tsuyu runs from roughly early June to mid-July on the main islands, starts in May in Okinawa, and barely touches Hokkaido. It brings heavy showers and grey skies rather than continuous rain, so a day is rarely lost outright. It also brings the hydrangeas, thinner crowds and cheaper rooms, which makes June a genuinely good-value month if you pack an umbrella and keep an indoor option per day.

Is August a bad time to visit Japan?

It is the hottest and one of the busiest months, and Obon in mid-August books out transport and hotels nationwide. It is also the best month for festivals and fireworks, which for many people is the reason to come. If you go in August, book two to three months ahead, build the days around the heat, and consider basing somewhere northern or high up.

Summer in Japan

Last updated: August 30, 2026

Owara Kaze no Bon dancers in black happi coats and deep woven straw hats moving in a low crouch down the stone-paved Suwamachi street in Yatsuo, Toyama, between dense crowds and rows of paper lanterns — Photo:Owara Kaze no Bon on Suwamachi street in Yatsuo, Toyama — three nights from 1 September, at the tail of the matsuri season.

Summer in Japan runs June to August, hot and humid, with July and August reaching the mid-30s °C in the cities. Tsuyu, the rainy season, covers roughly early June to mid-July on the main islands, and typhoon season builds through August. August is also the peak of matsuri season and holds Obon in mid-month, when the whole country travels at once — which together make it one of the busiest and most expensive periods of the year.

When is tsuyu, the rainy season?

Before the heat settles in there is tsuyu, roughly early June to mid-July across the main islands. Okinawa gets it earlier, from May, and Hokkaido largely escapes it. It is not a monsoon: expect grey skies and heavy showers rather than all-day rain. Hydrangea season, quiet temples and lower hotel rates come with it, which makes June one of the better-value months to travel. Carry an umbrella and keep one indoor option in reserve each day — and in a season this changeable, it is worth checking the weather forecast for the prefecture you are in the night before, since tsuyu showers are heavy but rarely all day.

How hot does Japan actually get in summer?

July and August run to the mid-30s °C in the cities, and the humidity is what catches people out — 35 degrees in Tokyo is not 35 degrees somewhere dry. Heat advisories are issued regularly and are worth taking at face value. The workable pattern is the local one: out early, indoors from about eleven to three for museums, department stores and a long lunch, then out again from late afternoon, which is when the festivals start anyway. Carry water and treat the convenience stores as cooling stops. And if July finds you near Nagoya, the July sumo tournament is an air-conditioned afternoon by design.

When is typhoon season in Japan?

Typhoon season builds through August and peaks in September. Most trips are unaffected, and those that are usually lose a day to cancelled trains and flights rather than to anything worse. Leave slack in an August or September itinerary and take the travel insurance seriously.

What is Obon, and how busy does it get?

Mid-August brings Obon, when people return to their family homes to honour their ancestors. Like Golden Week it moves the entire country at once: shinkansen sold out, domestic flights expensive, hotels in the smaller cities full. Unlike New Year, almost everything stays open. Two to three months of booking lead time applies to any August travel that crosses it.

Where do people go to escape the heat?

The highlands — Karuizawa, Hakone and Kamikochi in the Northern Alps sit several degrees cooler than Tokyo and have been summer boltholes for over a century.
Hokkaido — the one part of the country with a comfortable summer: dry, in the twenties, and lavender across Furano through July.
Okinawa and the southern islands — hot, but the sea is the point and it is warm from June.
Mount Fuji — the climbing season is early July to early September, the only window when the trails and mountain huts are open.

The compensation for all of it is that summer is when Japan is most alive outdoors: fireworks over the rivers, neighbourhood matsuri on almost every weekend, beer gardens on the department-store roofs, and evenings that stay warm long after dark.