Understanding Japanese Typhoons

Japan yearly takes hits from cyclonic storms of various intensities. Every time we have one, news agencies online overstate the dangers in order to improve their clicks. And then, nervous visitors share these, amplifying this fear into near-panic in some. As a permanent Japanese resident who's been here 20 years, I can tell you that the weather is almost certainly not as bad as you've been hearing. Understanding a bit more about our storms might help you in your tour planning. So let's get into them!

Powerful cyclonic storms are given different names depending upon where in the world they are located. Typhoons in the Pacific Ocean, Cyclones in the Indian Ocean and South Pacific near Australia/New Zealand and Hurricanes in the Atlantic. They are exactly the same; only the name differs. If you know one, you know them all.

Summer in Japan starts in June with our "rainy season" (about three weeks of near-daily rain, but not that heavy), followed by hot, humid weather with the odd chance of typhoons for July, August and on into the beginning of September.

Such storms all begin to the south of the country and as they move north they are drained of strength as they go. So, our local typhoons can be very nasty indeed to the small islands in the southwest of Japan (e.g. Okinawa) and the southwestern extremities of the mainlands in Kyushu.

But all cyclonic storms rapidly decay, often within a matter of hours, once the center "eye" hits any significant landmass. Within a day, they crumble into a few nasty rainstorms, and then those disperse and vanish over the next couple days. Because of the storms' movement north, and then the common impact with land in either Kyushu or Shikoku, it is very seldom that the mainland of Japan (Honshu) takes any serious damage from them.

How to read a typhoon prediction and tell if storms are dangerous

Follow all current typhoon tracks and predictions near Japan in English, here: https://www.jma.go.jp/bosai/map.html#5/35.422/136.078/&elem=root&typhoon=all&contents=typhoon&lang=en

Look primarily at the WIND SPEEDS (sustained and gust speeds are shown on the site linked below). If they're under 70 knots sustained wind speeds, the typhoon is no longer a "hurricane," but merely a "tropical storm" by US weather service standards. These cause severe localized flooding, but typically cause only minor disruption to travel.

Now, this looked like a fairly nasty typhoon just as the center passed over land. See the small red circle? That is the dangerous wind zone. Yellow circle means quite breezy and annoying, perhaps, but mostly not dangerous. So a good chunk of the country was (briefly) affected. Kyushu took a knocking.

A "record-breaking typhoon" in 2024, that caused many to cancel their Japan vacations.

But in the next image (showing less than 24 hours later!) our supposedly "huge" "powerful," "dangerous," and "record-breaking" typhoon was already well and truly shattered. At no point are wind speeds any higher than 30 knots—less than HALF the speed at which a storm can be classified as a cyclonic storm.

The storm itself is losing organization and spreading out. Individual parts are becoming isolated, individual rain showers of only moderate intensity. They may continue to cause localized minor flooding, but are little danger to anyone.

One day later... it's only a few rain showers.

But for various reasons other than storms, I still recommend to Japanese visitors that (if you can) avoiding summer outright is best. Japan is an awesome place to visit... September through May.

Hope that helps!