The rainy season started in western Japan on Monday, earlier than usual, the Meteorological Agency said.
It began four days earlier than average in southern Kyushu, nine days earlier in northern Kyushu and Shikoku, and 11 days earlier in the Chugoku region, the agency said.
The rainy season usually ends somewhere between July 14 and 21 in these regions.
The Kinki, Tokai and Kanto regions, as well as the Hokuriku area along the Sea of Japan, are expected to see cloudy or rainy days over the coming week, the agency said.