According to the Japan Meteorological Agency on Friday, the delay was caused by the temporary weakening of a Pacific high pressure system, which prevented the rain front from moving north, Xinhua news agency reported.

As high pressure over the Pacific Ocean strengthened, rain began to fall from Kinki to the Kanto-Koshien areas, heralding the rainy season.

Meanwhile, the rainy season ended a day earlier than usual in the southernmost Okinawa region, while active seasonal rainfall in the southern part of Kyushu caused heavy rain on Friday.

According to the agency, Kagoshima Prefecture was particularly affected, where a linear rainfall area caused very heavy rainfall.