The great diversity
Located in the Northern Hemisphere, Japan experiences the same seasons as Europe. However, the surface of Japan, from the Siberian regions in the north to the tropics in the south, or almost, and its double exposure to the Pacific and the Sea of Japan have created varied and sometimes paradoxical climates. Two currents, one cold(oyashio) and the other warm(kuroshio), meet in both the Sea of Japan and the Pacific. The cold current comes down from Siberia and the other one goes up from the equator. We can think that the meeting of these two currents has done a lot for the development of marine fauna and flora. But if these currents play a role in the development of life, the influence of the Asian landmass remains primordial. In Tokyo, the cold winter winds come from the northwest and load with water as they pass over the Sea of Japan and end up as snow on the western side. In summer, tropical winds blow up both slopes and manifest themselves in heavy rainfall in June and September, while July and August can become very hot and humid. But as a whole, the Archipelago is dominated by a very large variation of temperatures: one can go from -30°C in Hokkaido (the sea which borders Hokkaido, the Sea of Okhotsk, freezes in winter until April) to 40°C in Kyushu or Okinawa. If the winter is dry and cold in Tokyo, which is a rather pleasant climate, on the other side, on the Sea of Japan, the weather remains overcast and the sky is dotted with long snowy squalls.
Rainy and typhoon seasons
Although the term monsoon is more commonly used throughout Asia, it's the rainy season that prevails in Japan. Here, it's called tsuyu and generally lasts for six weeks, from June to mid-July. It's a scary time of year - just look at how much airfares drop most of the time. Sure, the rain is heavy, the humidity soars and the atmosphere is muggy, but the showers are also interspersed with moments of calm. It's a risk you have to take, but these aren't extreme conditions either, especially if you decide to stay in urban centers or flat areas. If you're lucky, you may find that this year is milder than others, with few continuous showers. Take along the famous transparent plastic umbrellas that abound in Japanese supermarkets during these rainy months. The Japanese summer also sees the arrival of typhoons (the equivalent of tropical cyclones or hurricanes). They strike Japan frequently between August and October, peaking in early September. Rainfall is abundant and winds violent. This phenomenon is not taken lightly in Japan, and every year, especially in rural areas, there is considerable loss of life and material damage. In addition to the typhoon itself, flooding, landslides and mudslides can be deadly. The Meteorological Agency announces typhoon itineraries a few days in advance. If you're vacationing in Japan at this time, stay inside your hotel or rental property, with a few provisions. Other disasters can strike Japan at any time:
Volcanic eruptions. These can now be predicted, reducing the risk of loss of life. Nevertheless, the Japanese are wary of the immediate consequences, i.e. landslides and mudslides.
Earthquakes. These are more difficult to predict, even if Japan has developed advanced technologies in this field. Earthquakes are frequent and can become formidable, especially in the most densely populated plains on the Pacific side (the Kōbe earthquake killed over 6,000 people in 1995). They can cause terrible tsunamis when they occur offshore. In the early afternoon of March 11, 2011, a powerful earthquake off Japan's east coast triggered a tsunami of rare violence, destroying several prefectures and claiming tens of thousands of lives. This massive natural disaster revealed the archipelago's shortcomings, particularly in the nuclear field, with the two Fukushima power plants severely damaged by the earthquake. In Japan, there is a before and an after to March 11, 2011. On January 1, 2024, another violent earthquake (magnitude 7.6) struck the Noto peninsula region. Unfortunately, the consequences were disastrous.
