The Japan Meteorological Agency announced Sunday that the Kanto-Koshin and Tokai regions have entered the rainy season.The arrival of the rainy season in the Kanto-Koshin region, which includes the Tokyo metropolitan area, is about the same time as the average year and one day later than usual for the central Tokai region, according to the agency.The declaration comes as a seasonal rain front is expected to bring wet weather to wide areas of the country in the coming days, with heavy rain forecast for parts of western and eastern Japan.