Photo/Illutration Pedestrians in front of Tokyo’s Shinjuku Station raise their umbrellas on June 14. (Sayuri Ide)

Clouds and rain dampened the start of the week and umbrellas were the rule on June 14, as the Japan Meteorological Agency declared the apparent late start of the rainy season in the Kanto-Koshin region.

The annual declaration came seven days later than usual and three days later than last year. It also arrived much later than the rainy day pronouncements for western Japan and the Tokai region in mid-May, which were much earlier than average years.

Kanto-Koshin and neighboring Tokai have typically entered the rainy season the same day or only a few days apart in recent years, according to the JMA.

But the agency declared that the rainy season began in Tokai on May 16, 29 days earlier than Kanto-Koshin. The JMA said it was the first time the season started more than 20 days apart in the two regions since 1951, when it began keeping such records.

“Tokai and Kanto-Koshin are usually affected by a seasonal rain front almost at the same time,” said an agency official.

Weather patterns in the two regions had been mostly identical since May as well.

But the JMA announced the start of the rainy season in Tokai along with the Kinki region earlier than Kanto-Koshin because the intensity and expanse of rain was more clearly seen in Tokai than Kanto-Koshin in real-time weather data and forecasts as of May 16.

The agency said weather conditions that enable it to declare the start of the rainy season had not been observed in Kanto-Koshin until June 14, resulting in the delayed announcement.

This year’s start of the rainy season announced by JMA is based on preliminary data. The agency releases the official start of the season for the year in fall every year after taking into account actual weather patterns observed by summer.

“The date of the start of the rainy season may change significantly,” a JMA official said.

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