Japan - weather in August

August is the last summer month in Japan, and on the main islands it is quite clearly the hottest month of the year, due to the delay in warming of the seas surrounding it. Generally, it is a quite warm month in the north, and decidedly hot and muggy in the center-south. The rains are frequent, although less than in June and July: in fact, August is the sunniest month among the summer ones, at least on the main islands.

The daily average temperature is 20 °C (68 °F) in the north of the island of Hokkaido (see Abashiri) and 22.5 °C (72.5 °F) in Sapporo.
On the island of Honshu, the average is 24 °C (75 °F) in the far north (see Aomori), 25 °C (77 °F) in Sendai, in the northeast, and 27 °C (80.5 °F) in Niigata, in the northwest. In the south-east, the average is 28 °C (82.5 °F) in Tokyo, while in the hottest cities, on the coast of the Seto Inland Sea (see Hiroshima, Okayama, Kobe, Kyoto), the average exceeds 29 °C (84 °F), and reaches almost 30 °C (86 °F) in Osaka.
On the small southern islands (see Okinawa, Ishigaki), which were warmer in the rest of the year, the average temperature is 29/29.5 °C (84/85 °F).
Sometimes heat waves can occur, during which the temperature can reach 38/39 °C (100/102 °F) in the large cities of central and southern Japan.

As for the rains, they are quite frequent and abundant in all the main islands, however, as mentioned, in the center-south, where June and July were very rainy months, in August the rains become a little less frequent. Instead, on the small southern islands (see Okinawa, Ishigaki), where the rainfall decreased in July, it increases in August, making it decidedly abundant.

However, everywhere there can be heavy rain, as well as strong winds and storm surges, when typhoons, the tropical cyclones of the western Pacific, arrive. We are in the period when typhoons in Japan are most likely, which will last until early October. The areas most at risk are, in addition to the small southern islands, the south-facing coasts, directly on the ocean, of the islands of Kyushu, Shikoku and Honshu.

In August, the sea in Japan is warm enough for swimming, as well as on the small southern islands, on the islands of Kyushu and Shikoku, and also on the island of Honshu, except in the northernmost part (see Aomori), where the sea is a little cool. Instead, on the island of Hokkaido, it is very cool on the west coast (see Sapporo), and even cold on the north coast (see Abashiri).




See also: Japan, the weather in July - September
The climate of Japan