When moving to Japan from my rather cold and snowy hometown, I had been warned about the high heat and humidity of summer in Japan and did my best to pack for it. Yet I was completely unprepared for the utter damp, sweltering misery I was about to experience.
This may seem surprising to those who have never experienced a Japanese summer. After all, in Japan, the leaves change in the autumn, and some places get an alarming amount of snow in winter, so some may assume the summers resemble those of temperate climates. In reality, Japanese summers are less like Canada’s and more like summers in Southeast Asia. They are often even worse and will get even hotter in the future.
What is Japan Like in Summer?
Photo: iStock/ winhorseStepping outside in the summer in Japan is like stepping into a sauna. The humidity and temperatures run very high, and many struggle with this. Japan’s climate varies from subarctic in the north to subtropical in the south. Still, most of it is categorized as humid subtropical.
The high temperatures and humidity affect most of Japan from the start of the rainy season around mid-June until the end of the typhoon season in late September, with August being the hottest month. According to the Japan Meteorological Society, data collected from 1991-2020 shows that in Tokyo, the mean daily maximum temperature for August is 31.3°C (88.3°F), and July’s mean daily maximum is almost as hot at 29.9°C (85.8°F).
In the early morning and evening, it cools down a bit, though not by much: the mean daily minimum for July is 22.4°C (72.3°F), and in August, it’s 23.5°C (74.3°F). These temperatures, combined with constant high humidity, mean that outside, there is little respite from hot, stuffy air, even in the evening.
- Summer in Japan is very humid and hot, with a humid subtropical climate.
- Summer lasts from mid-June to late September, with August being the hottest month.
- Early mornings and evenings offer little relief from the heat.
Summer Temperature Around Japan
Mean Daily Maximum in Major Japanese Cities in the Summer Months, 1991-2020
| June | July | August | September | |
| Sapporo | 21.8°C (71.2°F) | 25.4°C (77.7°F) | 26.4°C (79.5°F) | 22.8°C (73°F) |
| Tokyo | 26.1°C (79°F) | 29.9°C (85.8°F) | 31.3°C (88.3°F) | 27.5°C (81.5°F) |
| Osaka | 28 C°(82.4°F) | 31.8°C (89.2°F) | 33.7°C (92.7°F) | 29.5°C (85.1°F) |
| Fukuoka | 27.2°C (81°F) | 31.2°C (88.2°F) | 32.5°C (91°F) | 28.6°C (83.5°F) |
It’s Only Going to Get Hotter
Photo: iStock/ westHot and humid weather has been typical for Japanese summers since weather records began in the 1800s. The highest recorded temperature is 41.1°C (105.8°F) in two locations: Hamamatsu, Shizuoka Prefecture, in August 2020 and Kumagaya, Saitama, in July 2018.
In 2023, Japan had its hottest year and summer on record. In August 2023, Tokyo’s average daily maximum temperature was 34.3°C (93.7°F). Nearly 50,000 people across Japan required medical attention for heatstroke in July, and even in Hokkaido, almost 1,000 people were hospitalized in a week. The extreme heat affected harvests and fisheries, leading to higher food prices and diet changes. In 2024, heatstroke alerts were issued for 38 of Japan’s 47 prefectures. Temperatures reached 40°C (104°F) for the first time in several prefectures.
Like the rest of the world, climate change has significantly influenced Japan’s temperature. With an increase in average temperature, sea level rise and extreme weather, it will likely only get hotter.
How to Stay Cool
Photo: iStock/ Wako MegumiDealing with the summer heat in Japan can be challenging, but there are ways to stay comfortable and avoid heatstroke.
Here are some tips:
Wear the Right Clothing
Loose clothing made of natural, breathable materials like linen or cotton is best. Clothing that covers most of your skin can keep you cool and protect you from the sun.
The traditional Japanese yukata, a warm-weather kimono made from light cotton, is ideal for summer but generally confined to festivals. For everyday wear, choose clothing that mimics the effect of the yukata.
Use Traditional Cooling Methods
Traditional practices like carrying a folding fan (sensu) and wetting a towel (tenugui) to wrap around your neck can help you stay cool. Modern updates include portable battery-powered hand fans and cooling necklaces.
Sun Protection
Using parasols, wide-brimmed hats, and sunglasses can protect you from the sun. Wearing sunscreen is essential, and Japan offers some of the world’s best sunscreens and summer products.
Other Tips for Summer Survival
Photo: iStock/ Wako MegumiBecause of the heat and humidity, summer is often considered the worst season to visit Japan. However, it’s also the season for some of the best festivals and events. If you plan to travel to Japan in the summer or climb Mount Fuji, here are some places to visit in Japan that stay a bit cooler in the summer.
Try to do indoor activities during the hottest hours. When you are outside, try to walk in the shade as much as possible and walk slowly. Finally, staying hydrated and maintaining your body’s salt levels is essential. Drink plenty of water and pick up some salt candy tablets that are very popular in Japan. Or, if you want to try the traditional method of maintaining salt levels, eat umeboshi (Japanese pickled plums).
Do you love or hate summer in Japan? Is the heat too much? Let us know in the comments!
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Summer is not a “MONTH”
A little proofreading would help.
Thanks for the engagement, Bill.
I suppose it’s fine if you just visit and you have an array of fun, exciting things to do during said hot and humid weather.
Things change when you live here and the whole summer period is just another 2-3 months of day-to-day life where you sweat the second you close the front door…