Japan is experiencing another tortuously hot summer, with human-induced climate change driving up temperatures even in Hokkaido, where many people are not acclimated to heat.

Authorities are calling for utmost precaution as heatstroke alerts are being issued in 28 prefectures, from Hokkaido to Kyushu, for Friday.

On Thursday, the mercury hit 39 degrees Celsius in Kitami, a city in eastern Hokkaido, at around 2:30 p.m. — a record high — and 13.5 C above a 30-year average.