Is Japan's Rainy Season Dangerous?
- Yuki sensei
- Jun 16
- 3 min read
How to Stay Safe and Comfortable During 梅雨(Tsuyu) Season
What is 梅雨（Tsuyu）?
Japan’s rainy season, known as “tsuyu”, usually occurs from mid-June to mid-July. For many visitors from the U.S., this might be an unfamiliar season—not just rainy, but also hot and incredibly humid. In this article, I’ll introduce what this season feels like, what to be careful about during your stay, and how to protect yourself from heat-related illnesses like heatstroke.
What is Japan’s rainy season like?
During tsuyu, the weather is often cloudy with frequent and sudden heavy rain. But more than rain, the main challenge is humidity.
Temperature: 86–95°F (30–35°C)
Humidity: Often 70–90% or higher
Imagine walking into a steam room or boiler room. That’s what a day with 95°F and 80% humidity can feel like in Japan. Your sweat doesn’t evaporate, which means your body can’t cool itself down.
Common health issues during tsuyu
Heatstroke
Even though it’s not the peak of summer yet, many people suffer from heatstroke during tsuyu because their bodies can’t regulate heat effectively in such humid conditions. In June 2023, a record 7,235 people were transported to hospitals nationwide due to heat stroke. According to statistical data released by the Ministry of Internal Affairs and Communications of Japan, the cumulative number of people transported to hospitals nationwide due to heat stroke from May to September 2024 was 97,578. This was the highest number of people transported since the survey began in 2008. It is a very harsh environment even for people who are accustomed to the Japanese environment.
Fatigue, headaches, and sleep troubles
The sticky, heavy air can make people feel tired, and sleeping becomes harder due to muggy nights. Even if it does not result in heatstroke, sudden changes in temperature and humidity can often cause these types of ailments.
Tips for travelers during tsuyu
Choose the right clothes
Lightweight, moisture-wicking fabrics (like athletic wear) are better than 100% cotton.
Indoors can be overly air-conditioned, so bring a light jacket or cardigan.
Use portable gear
Handheld fans (ハンディーファン) are popular and USB-rechargeable.
Handheld fans (ハンディーファン) You can buy it for around 1000 yen. Cooling towels（クーリングタオル） can be soaked in water and worn around the neck.
Salt candy（塩飴 Shio ame） like sports drinks or salty candies are widely available at convenience stores and vending machines.
Stay hydrated – use vending machines!
Japan has vending machines everywhere. You can buy cold water, sports drinks, and non-caffeinated teas like barley tea (mugicha) easily. For example, Tokyo has over 20,000 vending machines!
Tips for staying comfortable in Japan’s rainy season
Plan indoor activities
Museums, art galleries, cafes, and shopping malls are perfect for rainy days.
Check weather apps often
Japanese apps like “Yahoo Weather” or “tenki.jp” offer hour-by-hour rain forecasts. Carry a foldable umbrella or rain poncho at all times. Also, Japanese TV programs always broadcast "熱中症アラート heatstroke alerts" along with weather forecasts. If you have a chance to watch TV at a hotel or other place, be sure to check it out!
Don’t ignore your body
If you feel dizzy, overheated, or develop a headache, rest in a cool place and drink an electrolyte-rich beverage.
Tsuyu can be tough—but manageable!
Japan’s rainy season is unique, but with good planning and the right tools, you can stay comfortable and safe. Make use of vending machines, handy fans, and drink lots of fluids. That way, you’ll be able to enjoy Japan even in its steamiest season!
At Yuki-sensei’s class, I offer fun and engaging lessons while exploring real aspects of Japanese life and culture. If you're wondering, “When’s the best time to visit Japan?” or “What should I prepare if I want to live there?” — feel free to ask! I'm always happy to support your journey toward understanding Japan.
See you in the next lesson!
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