Depending on where you’ve lived, you might have some experience with dealing with the copious amounts of humidity, wind, and rain that comprise a typical rainy season (梅雨, tsuyu or baiu) in Japan. However, if this is your first summer in the East Asia region it’s a good idea to prepare yourself (and your apartment) for the upcoming weeks of heavy rain.
This onslaught of moisture can cause mold and other problems in your apartment, and we’ll discuss a few ways to deal with this.
What/when is the rainy season?
The nuts and bolts science behind the rainy season is that it is the result of an almost stationary front of low-level warm air from east China all the way to across Japan. This lasts until the summer when the temperature rises and causes the warm air to be pushed north.
Written with the characters for plum (梅) and rain (雨) as the rainy season typically coincides with the harvesting of ripe plums, the rainy season in Japan depends on the region, but in general starts around the beginning of June and lasts for a few weeks until mid-July. During this time, the weather will be humid and storms will occur often. Although it there will be the occasional sunny day, the high probability for rain tends to make this season less popular for traveling/sightseeing.
Meteorological agencies track the beginning and ending of the rainy season for various regions in Japan. Using resources like these, you can plan around preparing for the rainy season.
|Region||Average Start||Last Year’s Start|
|Okinawa||May 9||May 16|
|Amami||May 11||May 14|
|Kyushu (South)||May 31||May 31|
|Kyushu (North)||June 5||June 26|
|Shikoku||June 5||June 26|
|Chugoku||June 7||June 26|
|Kinki||June 7||June 27|
|Tokai||June 8||June 7|
|Kanto||June 8||June 7|
|Hokuriku||June 12||June 7|
|Tohoku (South)||June 12||June 7|
|Tohoku (North)||June 14||June 15|
Laundry in the rainy season
Most residents in Japan rely on air-drying their clothes. If you happen to have access to a drying machine, then the rainy season might not affect your laundry habits as much.
But, for the rest of us, when it becomes difficult to dry clothes outdoors due to rain and humidity, we have to find ways to adjust. If you just hang your wet clothes inside your apartment, chances are they’ll dry too slow and will develop a damp/mildewy smell. To make sure your clothes stay fresh and clean even in the midst of the rainy season, a good tip is to turn your air-conditioning unit on the “dehumidify” option if it has one. This will help your clothes dry quicker so there is less time for mildew to develop. It’s important to have some circulation of air when drying your clothes indoors, so even having your fan pointed at your clothes is better than nothing!
Another option is to hang your laundry in your bathroom and turn on the ventilation fan. Some bathrooms are equipped with room to hang clothes that will make this easy, but you can also find home goods made for this purpose. A 浴室用物干し竿 (washroom drying bar) should fit in a standard bathroom and provide something on which you can hang your clothes for drying.
If you live close to a coin-laundry you might find it convenient to use the dryers located there. However, then you’ll have to deal with the issue of transporting your dry clothes back home without getting caught in the rain.
Dealing with mold and bacteria
During this season it might feel like you will forget what a non-humid day is like. When there is a lot of moisture in the air for a prolonged period of time, mold and bacteria will thrive. Being aware of this and taking proactive measures to stop any ingress of mold/bacteria will help keep you sane (and also can possibly save you money on more expensive mold treatments).
One common area for mold to grow is around windows. The most effective way to prevent this is to keep your apartment dry through using the dehumidify setting on your air conditioner (or with a dehumidifier appliance). This and wiping any condensation from the nooks and crannies around your window will help make sure that mold doesn’t have the moisture it needs to grow. But, if you do spot some mold growth, there are products you can purchase to deal with it. Products like カビキラー are sprays that work for most surfaces.
Bathrooms and washrooms are other areas where the high moisture and temperature of the rainy season tends to result in mold growth. Since this is a common occurrence in Japan, there are preventative home goods that you can buy to help manage unwanted mold in your washroom! The 防カビくん series of washroom products coat your washroom in silver nanoparticles which have anti-bacterial and anti-fungal properties.
And for all around use, there are mold and odor absorbing products that you can stick in a variety of areas. Places like your kitchen sink, shoe box, closet, etc. all might be a little bit more humid than normal during this season and lead to mold growth. These small adhesive mold prevention goods, such as the ones by Cogit, are perfect for fitting into all these areas to give you peace of mind in the rainy season.