People in Sapporo shivered through frigid conditions on Friday as the city recorded a daytime high of minus 10.1 degrees Celsius, making it the first time in 40 years that the mercury has failed to reach minus 10.
Weather officials say an air mass flowing in over the capital of Japan's northernmost prefecture, Hokkaido, is the coldest on record. At an altitude of 1,500 meters, the air measured minus 24.4 degrees.
Some other cities in Hokkaido endured even more harsh conditions. In Oketo Town, the temperature plunged to minus 22.7 degrees, and in Rikubetsu Town, it was minus 20.6 degrees.
Police say three people in Rumoi City passed out from suspected carbon monoxide poisoning while apparently using a power generator in a closed room.
Hokkaido Railway Company said that as of 5 PM, it had been forced to cancel 105 train services.
Weather officials are forecasting that temperatures on Saturday morning will be even colder due to radiation cooling. They say the icy conditions are likely to continue for about a week.