Japan’s humid summers: a survival guide

Japan's humid summers: a survival guide

Once the rainy season starts, Japan is engulfed in heat and humidity to stay for months. They make the air feel heavy and bring an odd smell to the cities.

Even summer loving individuals, who miraculously don’t find the air suffocating, have to take precautions to avoid the damage humidity can do to you and your belongings.

What is the weather like in summer?

Girl standing in the summer rain.

In Tokyo, temperatures in the summer are around 30-35°C (86-95°F), almost something one could get used to. Due to the humidity though, it always feels like you are covered in a blanket of warmth, or rather a film of water with your clothes sticking to your skin, and sweat pearling from your forehead.

Japan rainy season falls into the summer months, bringing humidity in Tokyo to a monthly average of 70-80% from June through August, with its peak in July. The comfort level for humidity is said to be around 40%. So, with humidity double of the average Joe’s comfort level, it is no surprise that the air is stifling and you feel exhausted.

Survival tips against humidity

“If it’s too hot outside, let’s just stay inside!” This is a great plan, and it will work in most places except your own home. On the other hand, trains, shopping centers and the like will be an AC heaven, so cold you might need a jacket (or catch a nasty summer cold).

How to lower humidity in your room

Chances are your room will feel even more hot and humid than the outside. Why? Japanese houses usually are not insulated. This lets the warmth and humidity creep in, making the inside temperature the same as outside. And if you then don’t open the windows to have your AC last just a little bit longer … the air will grow stale and you are miserable.

Open your windows to save yourself a quite literal headache. Not only will the fresh(er) air flowing in do you good, especially when it’s hot outside opening your windows will lower the humidity inside your room.

To battle the heat use fans for airflow. Add an AC and dehumidifier, set both to the dry setting, and you can decrease both temperature and humidity in your room.

For your bathroom, kill two birds with one stone, and try taking a cold shower during the day. It will not only cool you down but also make the mold uncomfortable (or so Japanese housewives will tell you) because the cold water lowers the room temperature and gets rid of soap remnants and other things that might favor the growth of mold.

If you do find mold in your apartment take care of it ASAP but not before looking up safe removal methods.

How to prevent unpleasant smells

Your house is not the only thing at risk. High humidity can impact your clothes too. They might smell even after you washed them. Easily mistaken for a moldy bouquet, it is usually just the result of the humidity, allowing bacteria to grow.

Preventing bad smell starts when you wash your clothes. Worn in the humid weather, your clothes will be damp themselves. Leaving them damp with sweat with no way to dry, for a longer time will lead to unpleasant smells. To avoid this most Japanese are doing laundry every single day.

To further prevent smell, don’t leave your laundry in the washing machine and dry it outside instead of inside your room. If you don’t have space to hang outside, put everything so the AC is blowing on it and change the setting to dry for the time.

You can also buy 除湿じょしつ items to get rid of excess humidity in fabrics.They are available in all shapes and sizes, ranging from small シリカ bags or pillows with water absorbing contents for your drawers, to big 除湿じょしつシート that fit under a futon. A cheap alternative is newspaper, you can use it for shoes and hats too.

Once your clothes smell the way they should, all that’s left to worry about is a climate appropriate outfit.

How to survive outside

Japanese ladies love to cover up in the summer. Anything available is being used to keep the sun away and the skin white. You don’t have to follow this fashion. As long as you are not visiting shrines and temples, or attending a business function, shoulder-free and short pants are entirely acceptable.

For guys, there are still many occasions where short pants and sleeveless are not an option in Japan. Even then short-sleeves, clothes made of cotton, and a cap can help defend against the worst of Japan’s sun. There are also “cool” undershirts and basic clothing items made of materials that dry quickly and will at least help you “look” chill.

Cooling sprays, mists, sheets, sticks – Japan’s shops have many items that may not offer protection from the humidity, but at least help you fend off the heat, even if for a few minutes.

How to waterproof your makeup and perfume

When humidity makes every day bad hair day, but you still want to look good, try some of Japan’s large collection of water-proof makeup. While you are at it, go easy on perfume during the summer months, the heat and humidity will cause oxidation which will change the smell of your favorite perfume to that of a drowned cat.

Try toning it down a notch with citrus, jasmine and other fresh smells. They might not last as long, but you will be happy for it (this goes for guys too).

How to protect your food

Back to mold, this time on your food. Japanese summers make your food grow bad and furry quicker too. Putting everything into the fridge, won’t prevent anything, but if you avoid putting wet things in, you can prolong your foods lifetime.

Alternatively, you can look for 乾燥性かんそうせい, something with drying properties. Double check that 食品用しょくひんよう (suitable for food products) is written on the package.
You’ve probably seen them many times, these small plastic bags inside the snacks packages. You can get the cheap plastic ones, or classier versions made from natural materials and aesthetically designed.

Blooming ajisai next to train tracks

These 5 tips above, should help you make sure that your belongings do not suffer from the humidity. Otherwise I hope you enjoy the Japanese summer with its seasonal foods, pretty flowers and almost weekly festivals. When seeing one of the fireworks at the end of summer, somehow it was all worth it.

If you still hit a day too hot and humid to bear, grab your wallet, got to your local drug store or 100-yen shop and shop for the newest gimmicks while cooling down under their AC.

Others also read



After traveling around for a while, I found my home in Tokyo. Now working in Shinjuku and discovering something new about Japan every day.