The Tokyo metropolitan area is expected to be extremely hot this weekend, with the mercury forecast to top 35 degrees Celsius in some places, prompting warnings over the risk of heatstroke.

Temperatures were already high in other parts of Japan on Friday, with the city of Nagano registering 35.1 C just after noon and 36.7 C recorded in Niigata Prefecture’s Takada district, according to the Meteorological Agency.

In the week through Sunday, 1,337 people nationwide were sent to the hospital due to suspected heatstroke, according to the Fire and Disaster Management Agency.

The maximum temperatures on Saturday are expected to be 36 C in Kumagaya, Saitama Prefecture; 35 C in Maebashi, Gunma Prefecture; and 36 C in Saitama’s Chichibu, according to the agency. It also predicts that temperatures will reach 33 C in Tokyo.

The agency’s two-week forecast for the Kanto-Koshin region shows sunny weather and high temperatures throughout next week, prompting some meteorologists to wonder if the rainy season will end exceptionally early this year.

“The meteorological agency may need to consider (next week) whether the rainy season has ended, since the forecasts only show sunny and scorching hot days,” said Yuji Sugie, a meteorologist for broadcaster Nippon TV.

Typically, the rainy season starts in early June and lasts until mid-July on the mainland.

The earliest recorded end of the rainy season in the Kanto-Koshin region was June 29 in 2018.

Last year, the rainy season in the region ran from June 14 to July 16, starting later than usual.