Kashiwa Life Chapter Two: The Rainy Season

What is the rainy season?

The rainy season, or tsuyu, takes place every year in all of Japan’s islands except for Hokkaido and the Ogasawara Islands. Tsuyu means “plum rain” and refers both to the the plum harvest in Japan and the rains that sweep through the country. In Honshu it typically takes place from the beginning of June to the middle of July, but the exact timing varies by year and location. It doesn’t rain every day during the rainy season, but it rains a lot and becomes very humid. Tsuyu happens when a cold high-pressure front from the north meets the warm, humid, low-pressure front coming through from the south. 

So what? Rain is not a big deal.


This is different. The rain is only a slight problem. The real killer is the humidity.

You will suddenly be thrown into a war with mold and cockroaches will awaken from their slumber to terrorize the public once again.

Everything wet will remain wet.

Food will go bad in the blink of an eye.

Let me share with you some of the secrets to getting through tsuyu.

A Japanese man wearing a clear poncho

Get rain gear. This one is kind of obvious. Since you can expect rainy weather about 45% of the time, rain gear is vital if you want to remain comfortable. If you tend to lose your umbrella like I do, look for an umbrella at a 100-yen shop or a convenience store and decorate the handle with washi tape so nobody swipes it from you. Otherwise, treat yourself to a cute or quirky one like the samurai sword ones or those color-changing ones! Another thing I would invest in is a good pair of rain boots. Sneakers are somewhat tolerable if you get stuck in the rain, but they will take forever to dry and potentially become moldy. I splurged on a nice pair of boots made with neoprene and it was 100% worth the money. In their 7+ years of service, they have never once gotten moldy or leaky on me. If you want to be extra prepared, you could also grab one of those rain parkas at Uniqlo that fold up really small and throw it in your bag just in case. Fortunately, most stores in Kashiwa will have these products front and center so you can easily find what you need. 

Always know where your towel is. This is good advice anyway (RIP, Douglas Adams), but especially so during the rainy season. You will spend a lot of the next month or so feeling wet, be it from the rain or your own sweat. During those times, a towel is a godsend. There are tons of places that sell these, including 100 yen stores. Trust me on this one. You don’t want to be stuck in a waiting room completely drenched.

Bring a change of clothes with you. If a towel can’t do the trick, changing clothes will definitely help you dry off. There are a lot of companies like Uniqlo that make lightweight clothing with wicking properties. I would aim for these. Also, note that wearing sleeveless shirts like camisoles or tank tops will make you stick out and people might mistake you for a tourist. These clothes are considered revealing in Japan, even for men. 

Check the weather constantly. You’ll need to prepare yourself for any rainstorms or potential openings where you can get your laundry outside to dry. Drying your laundry inside your bedroom during this season is a pretty good way to get a room full of mold. I use Yahoo Weather, but here's what apps are popular with foreigners living in Japan. 

Cleaning mold with a sponge and foaming spray

Bring out the anti-mold reinforcements. The war with mold is a brutal one, but there are plenty of allies out there to fight alongside you. Kabikira (カビキラー) is a bleach spray that works awesome against mold and will become your best friend. Some products absorb moisture so you can prevent the mold from growing in the first place. They even make versions of these products to put inside your shoes! Here's a list of the most popular ones in Japan. The stores around here will have you covered, as they move these products to the front around this time. Make sure to use the dehumidifier setting on your air conditioner (the one that says 除湿), turn on the fan in the bathroom and/or open a window.

Make your place inhospitable to cockroaches. Unfortunately, you will have to fight a war on two fronts, especially if you live in an older home. That’s because all the conditions that help mold proliferate also help cockroaches proliferate. Fortunately, many of the same treatments apply to cockroaches. They don’t tend to like a clean home and they prefer high humidity environments. However, this will not completely eliminate them from your life so there are other things you must do to keep them out. Sprays are the ultimate weapon as they kill cockroaches on contact and/or deter them from entering in the first place. Be sure to ventilate the room after using these sprays though, because the fumes aren’t good for us either. Baits are also great because the roaches take them back to their nasty roach families. Just about every convenience store and pharmacy in town carries these products because nobody likes cockroaches! And please, don’t leave any water, oil, cardboard or food out and about. They are attracted to these things. Here's a list of products you might want to try. 

Be familiar with the flood maps. Where there's a lot of rain in a short amount of time, there is flooding. While floods can happen during any season, it's always a good idea to be prepared when you know you'll be getting a lot of rain. Most of Kashiwa remains high and dry, but you'll have to be careful around Teganuma or the Tone River. Know where your nearest flood shelter is in case of an emergency. We have flood hazard maps available for anyone who needs one!

A person practicing good food safety by checking the temperature of roast chicken

Be extra careful about food safety. Remember when I said this season has the prime conditions for mold growth? Well, there’s another baddie you’ve got to watch out for: bacteria. Bacteria tend to like warm, humid places and will quickly infest food products you leave out during this season. That’s why cases of food poisoning and gastroenteritis tend to increase in June and July. The best way to avoid this is to be careful about eating raw food, keep things refrigerated, and throw out anything that looks suspect regardless of the expiration date.

Change up your skincare/ hair care products. Because of the intense humidity, it's not uncommon for people to find that the products they rely on during other seasons are rendered ineffective. The humidity can also make you feel quite uncomfortable. I already have an article about summer skincare for every skin type, so check that out to find some good products for you. Additionally, I would say it’s a good idea to keep some baby wipes on you. You can get the regular ones pretty cheap from a 100 yen shop, but the more expensive ones sometimes have different scents and some even have cooling properties! My hair care article will be out in a couple of weeks, so hang in there! 

This article is written by:

United States




Hey guys! I’m Sydney, your friendly neighborhood foreigner! I moved to Japan in 2014, but I came to Kashiwa in 2019. Despite my name, I’m American not Australian.

When I first arrived in Japan, I was so relieved to find articles written by other foreigners about how to make my way in my new country. Now that I’ve been here a while, I’d like to share what I’ve learned as well and pay it forward.