A heat wave enveloped much of Japan on Saturday, sending temperatures soaring beyond 30 degrees in more than 300 places nationwide, the Meteorological Agency reported.

The agency also said the rainy season in the Kanto-Koshin region, which includes the Tokyo metropolitan area, is believed to have ended 15 days earlier than usual.

On Saturday, the Hokuriku region facing the Sea of Japan experienced a “moshobi,” or “day of extreme heat,” with temperatures exceeding 35 degrees, the agency said.

The heat prompted the agency to issue heatstroke advisories in some regions, including Kanto-Koshin and Tohoku, recommending that people hydrate often and use air conditioning if necessary.

According to the agency, just after midday the mercury hit 36 degrees in Koga, Ibaraki Prefecture, and 35.9 in Tatebayashi, Gunma Prefecture.

Other hot spots included Itoigawa, Niigata Prefecture, at 35.8 degrees, Mitoyo, Kagawa Prefecture, at 35.4, Miyazu, Kyoto Prefecture, at 35.2, Kanazawa, Ishikawa Prefecture, at 35.1, and Iga, Mie Prefecture, at 35.

Central Tokyo meanwhile reached 33 degrees, the agency said.

Surprisingly, the rainy season in Kanto ended earlier than in some western regions, such as Kinki and Shikoku, it said. This is because a high-pressure system over the Pacific reached Kanto first by coming from the southeast. Usually, the summer anticyclone comes from the south, arriving in western regions first.