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 is the rainy season that prevails in Japan. It is called tsuyu here and this period usually lasts for six weeks, between June and mid-July. It is a period that can be frightening, just look at the price of airline tickets that drop most of the time. Sure, the rain is heavy, the humidity is high and the atmosphere is muggy, but the showers are also interspersed with moments of calm. It's a risk to take, but these aren't extreme conditions either, especially if you decide to stay in urban centers or flat areas. If you are lucky, you may find a year that is milder than others, with few continuous showers. Take the famous clear 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 frequently hit Japan between August and October, with a peak in early September. The rainfall is abundant and the winds are violent. This phenomenon is not taken lightly in Japan and every year, especially in rural areas, there are many human losses and material damages. In addition to the typhoon itself, it is the floods, landslides and mudslides that can be deadly. The Meteorological Agency announces, a few days in advance, the route of the typhoons. If you are on vacation in Japan at that time, stay inside your hotel or rental property with some supplies. Other disasters can strike Japan at any time:
Volcanic eruptions. They can now be predicted, which reduces the risk of loss of life. However, the Japanese are more wary of the immediate consequences, i.e. landslides and mudslides.
Earthquakes. They 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 plains of the Pacific side which are the most populated (the Kōbe earthquake killed more than 6,000 people in 1995). They can cause terrible tsunamis when they occur offshore. On March 11, 2011, in the early afternoon, a powerful earthquake off the eastern coast of Japan caused a tsunami of rare violence, which destroyed several prefectures, and killed tens of thousands. This natural disaster of great magnitude revealed the deficiencies of the Archipelago, in particular in the nuclear field, the two power plants of Fukushima being severely damaged following the earthquake. There is, in Japan, a before and after March 11, 2011.
