Economy & Tech

Japan's Rainy Season Delayed: Latest Forecast

The rainy season in the Kanto region including Tokyo is predicted to start around June 16, eight days later than usual. A late start is expected across Japan.

Published

5 months ago

June 12, 2024

The Sankei Shimbun

Rainy season began in Okinawa on May 21. Naha, Okinawa. (©Sankei by Naoki Otake)

According to the Japan Meteorological Agency's (JMA) latest forecast on June 10, the Kanto-Koshin region is expected to enter the rainy season around June 16. This is eight days later than the usual onset of the rainy season, which typically occurs around June 7.

If the rainy season front does not move northward by June 16, some areas may see temporary clear skies due to high pressure. This could result in a significant delay in the start of the rainy season, especially in regions like Kanto-Koshin.

*People walking with umbrellas in Naha, Okinawa on May 21. (©Kyodo)*

Northward Shift

According to the JMA, this year, the northward extension of the Pacific high-pressure system is weaker. Additionally, the westerly winds are meandering further south than usual, causing a delay in the northward movement of the rainy season front.

The JMA forecasts the stationary rainy season front, lingering south of Japan's Nansei Islands, will move northward towards Honshu after June 15. This shift is expected as the Pacific high-pressure system strengthens. It also anticipates that the rainy season will begin in Kyushu to Kanto around this time, at the earliest.

*Data from the Japan Weather Association*

Late Onset

If the rainy season starts after June 17, areas like Kanto-Koshin could experience it beginning in late June. Rainy season onset in the Kanto-Koshin region occurred as late as June 22 in 1967 and 2007, a phenomenon not observed for 17 years.

Northern Kyushu and the Chugoku region are expected to experience the start of the rainy season around June 16. This would mark the fifth latest recorded occurrence in the respective areas.

Across all regions, the onset of the rainy season is anticipated to be later than usual this year. Okinawa and Amami have already entered the rainy season, experiencing delays of nine and eleven days, respectively, compared to most years. Additionally, southern Kyushu, also delayed by nine days, and Shikoku, delayed by four days, have seen the start of the rainy season.

(Read the article in Japanese.)

Author: The Sankei Shimbun