Temperatures in Japan's northern city of Sapporo -- famous for skiing -- on Monday passed 25 degrees Celsius at the earliest point of any year on record, a weather agency official said.
Sapporo, the main city on the island of Hokkaido, hosted the 1972 Winter Olympics and each February holds a snow festival where massive ice sculptures draw tens of thousands of visitors.
"The temperature in Sapporo hit 26 degrees... and is still rising," Shuichi Yoshida, an official at the regional headquarters of the Japan Meteorological Agency, told AFP in the early afternoon.
It is the earliest that temperatures in the city have passed 25 degrees Celsius (77 Fahrenheit), which the JMA classifies as a "summer's day", since records began there in 1877.
Over 30 degrees is classed as "mid-summer" while over 35 is "extremely hot", according to the JMA's system.
"We can't rule out the possibility that climate change has played a role in the high temperature," Yoshida said.
Other factors such as high-pressure systems may have also contributed, he added.
On average between 1991 and 2020, the highest temperature in Sapporo on 15 April was 11.5 degrees Celsius, the JMA says.
Before Monday the earliest 25-degree day in the city was 20 April 1998, when the mercury reached 25.2 degrees.
Globally, this year has already been marked by climate extremes and rising greenhouse gas emissions, spurring fresh calls for more rapid action to limit global warming.
Every month since June 2023 has beaten its own "hottest-ever" tag -- and March 2024 was no exception, according to Europe's climate monitor.
The JMA also says that climate change is making Japan's famous cherry blossoms appear earlier on average.
Last year's cherry blossoms, or sakura, began to flower in Tokyo on 14 March, tied for the earliest ever alongside 2020 and 2021.
"Since 1953, the average start date for cherry blossoms to bloom in Japan has been becoming earlier at the rate of approximately 1.2 days per 10 years," the JMA says.
This year, however, the delicate pink and white blossoms arrived later than usual because of cold weather.
Sapporo had been seen as a favorite to host the 2030 Winter Olympics, but the city gave up its bid in October after corruption scandals connected to the 2020 Tokyo Games.