Photo/Illutration Takafumi Umeda, who heads the Japan Meteorological Agency’s abnormal weather information center, explains drastic revisions to the JMA’s preliminary estimates on the end of this year’s rainy season during a news conference on Sept. 1. (Takuya Miyano)

The Japan Meteorological Agency is putting a damper on its earlier announcement that this year’s rainy season likely ended in June in many parts of Japan, adding another month to the estimated date.

The agency previously announced on June 28 that rainy season appeared to have ended for the Kinki, Hokuriku, Chugoku, Shikoku and northern Kyushu regions.

At the time, that was heralded as the first time for a June ending in these areas since record-keeping began in 1951.

But it turned out that the rainy season ended later than usual across most of the country, according to the official data released by the JMA on Sept. 1.

Agency officials attributed the drastic revisions to the preliminary data to the difficulty in predicting how the westerly winds would blow.

The new revised ending dates showed July 22 for southern Kyushu and July 23 for Kinki, both 25 days later than the preliminary estimate.

The rainy season ended on July 23 in the Tokai and Kanto-Koshin regions, 26 days later than initially estimated.

Agency officials said they had never drastically revised the preliminary data for so many areas before.

The JMA did not release the official end of the rainy season in Hokuriku and the Tohoku region, saying it could not specify the dates for these areas.

The end of the season remained unchanged from the initial estimate in the Okinawa and Amami regions on June 20 and 22, respectively.

The agency reported that westerly winds shifted northward over areas near the Japanese archipelago in late June, bringing an unusually intense heat to many parts of the country for about 10 days, which is rarely seen even in mid-summer.

But the westerlies moved southward from mid-July onward, resulting in about 10 days of cloudy and rainy weather across most of the nation.

Agency officials concluded that they should extend the period of this year’s rainy season to cover the duration of cloudy and rainy days in mid-July, said Takafumi Umeda, who heads the JMA's abnormal weather information center.

Temperatures also soared to unusually high levels in late June 2005, which is called a "break" in rainy season. But the heat observed in late June was particularly severe, according to the agency.

"It was unusual and can be described as abnormal weather," said Umeda. 

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