How to Sleep Better During Summer in Japan: Tips for Hot and Humid Nights

Summer nights in Japan can be surprisingly difficult, especially if you are not used to high humidity.

When I first moved to Japan, I expected the hot temperatures. What surprised me much more was how heavy and sticky the air could feel, even late at night.

You may find yourself lying awake for a long time, waking up several times during the night, or feeling tired even after spending enough time in bed.

If that sounds familiar, you are definitely not alone.

Since living in Japan, I have noticed that summer nights often remain uncomfortably warm even after sunset. In Japan, nights when the temperature does not fall below 25°C, or 77°F, are called nettaiya (熱帯夜), meaning “tropical nights.”

For foreigners who are new to Japan, sleeping through these hot and humid nights can take some adjustment.

In this article, I would like to share a few practical summer sleep tips based on what I have learned while living in Japan.

Why Is It So Hard to Sleep During Summer in Japan?

One thing I learned after moving to Japan is that humidity can feel just as uncomfortable as heat.

Before we fall asleep, our body naturally begins to release heat and lower its internal temperature. This process helps us feel sleepy.

However, when the bedroom is hot and humid, it becomes more difficult for the body to cool down.

Japan’s summer humidity also makes sweat evaporate more slowly. That is why a temperature that might feel manageable in a dry country can feel much hotter and more uncomfortable in Japan.

Sheets and pillows may also begin to feel damp or sticky during the night. This can lead to more tossing and turning and may cause you to wake up repeatedly.

Sleeping well during a Japanese summer is usually not about changing only one thing. The room temperature, humidity, bedding, and your bedtime habits can all affect how comfortably you sleep.

Don’t Be Afraid to Use the Air Conditioner

Some people in Japan still believe that leaving the air conditioner on overnight is unhealthy.

You may hear comments such as:

“Sleeping with the air conditioner on all night is bad for your body.”

However, Japan’s summer nights can remain very hot and humid, and trying to tolerate the heat may lead to poor sleep and exhaustion the next day.

Personally, I have found that using the air conditioner properly is much better than waking up several times because the room has become too hot.

There is no single perfect temperature for everyone. Start with a setting that feels comfortable and adjust it gradually.

The goal is to avoid both overheating and becoming too cold.

Try not to let the air blow directly onto your face or body. Instead, direct the airflow toward the ceiling or a wall so the cool air can circulate more gently around the room.

A fan or circulator can also help distribute the air more evenly.

Using a timer may seem like a good way to save electricity, but the room can quickly become hot again after the air conditioner turns off. On especially warm nights, keeping it on at a moderate setting may help you sleep more comfortably until morning.

Try the Dehumidifying or “Dry” Mode

For me, humidity sometimes affects sleep even more than temperature.

On very humid nights, the dehumidifying or “dry” mode on a Japanese air conditioner can make a noticeable difference.

Reducing the humidity can make the room feel cooler and less sticky, even without lowering the temperature very much.

Depending on your air conditioner, you may see this mode written as 除湿 or ドライ on the remote control.

The best choice between cooling and dry mode depends on the temperature, humidity, and the type of air conditioner you are using.

I usually choose the setting based on how the room feels that evening rather than using the same mode every night.

Cooling Bedding Can Make Summer Nights More Comfortable

Japan has a wide range of bedding designed for hot and humid summers.

Cooling mattress pads, pillow covers, lightweight blankets, cotton sheets, gauze, and linen bedding can all help make the bed feel more comfortable.

Even a simple change in fabric can improve airflow and reduce the sticky feeling caused by sweat.

I also find it helpful to wash pillow covers and sheets more frequently during summer.

It may not be realistic to wash all the bedding every day, but changing the pillow cover or mattress pad regularly can make the bed feel fresher.

When choosing summer bedding, it is useful to consider not only how cool it feels at first, but also how breathable it is and how easy it is to wash.

I plan to write a separate article about useful cooling items for summer in Japan, including bedding and other products that may help during hot nights.

A Lukewarm Shower or Bath May Help You Relax

When the weather is extremely hot, taking a cold shower before bed may seem like the most refreshing option.

However, a lukewarm shower or bath may help you relax more effectively.

As your body temperature gradually drops afterward, it may become easier to settle down for sleep.

A very hot bath can leave you feeling more awake, so it is better to choose a comfortable temperature and avoid staying in too long.

Staying hydrated is also important during the Japanese summer.

However, drinking a large amount of water immediately before bed may cause you to wake up during the night to use the bathroom.

I find it more comfortable to drink water regularly throughout the day and only have a small amount before going to sleep.

Put Your Phone Down Earlier Than Usual

Many of us tell ourselves that we will check our phone for only five minutes.

Then thirty minutes or even an hour passes before we realize it.

During humid nights in Japan, it is easy to keep scrolling because you already feel too uncomfortable to sleep. Unfortunately, this often makes bedtime even later.

The bright light from smartphones and tablets can also make it harder for the brain to prepare for sleep.

Try putting your phone down around thirty minutes before bedtime.

Dimming the lights, reading a book, or listening to quiet music may help your body and mind begin to relax.

Keeping a regular sleep schedule can also be helpful.

Sleeping very late on weekends may make it harder to fall asleep at your usual time, so try not to change your waking time too dramatically.

Don’t Try to Tough Out Japan’s Summer Heat

One thing I have learned from living in Japan is that there is no benefit in forcing yourself to endure the heat.

Using the air conditioner, adjusting the humidity, changing your bedding, and improving your bedtime routine are all practical ways to take care of yourself.

Personally, I find humid nights more difficult than simply hot ones. Sometimes switching from cooling mode to dry mode makes the bedroom feel completely different.

Small adjustments can have a bigger effect than expected.

A cooler bedroom, breathable bedding, a relaxing shower, and less screen time before bed may help you sleep more comfortably during Japan’s summer.

I also wrote about why summers in Japan feel so hot and humid, along with some basic heat safety tips. That article may be helpful if you are still adjusting to the Japanese climate.

Summer in Japan is not only about enduring the heat.

Enjoying cold barley tea, fresh watermelon, and a quiet evening with family can also make the season feel a little more special.

With a comfortable bedroom and a few simple habits, it becomes easier to rest well and still enjoy the small pleasures of a Japanese summer.

What helps you sleep better during summer in Japan?

I would love to hear what works for you. 🌙🎐🍉