The coldest air mass of the season continues to bring snow, mainly to areas along the Sea of Japan coast from western to eastern Japan. The mercury has dropped below zero Celsius across the country.
Weather officials are advising people to refrain from non-essential outings and watch out for icy road conditions. They also warn that water pipes could freeze.
The Meteorological Agency says a strong winter pressure pattern is bringing an influx of cold air.
Okuizumo Town in Shimane Prefecture saw 18 centimeters of snow during the three hours through 4 a.m. on Wednesday.
As of 4 a.m., snowfall had reached 1.54 meters in Daisen, Tottori Prefecture, and 1.05 meters in Nozawaonsen Village, Nagano Prefecture.
Snow has also accumulated at lower elevations where there is usually little snow. Snowfall reached 13 centimeters in Kyoto City and 6 centimeters in Hiroshima City. The weather conditions have been affecting transportation in the Kansai region and elsewhere.
Winds have also intensified from northern to western Japan mainly along the Sea of Japan coast. A peak gust topped 100 kilometers per hour in Sakata City's Tobishima in Yamagata Prefecture shortly before 4 a.m.
The lows dropped to minus 12.1 degrees Celsius in Sapporo City, minus 7.3 degrees in Sendai City and minus 5.6 degrees in Niigata City.
The winter pressure pattern is expected to stay until Thursday, bringing heavy snow and blizzards mainly to areas along the Sea of Japan coast. Heavy snow is also possible in lower elevations along the Pacific.
Temperatures are forecast to plunge across the country to the lowest level in a decade.
Weather officials are urging people to be careful of heavy snow, blizzards, frozen roads and other effects on transportation, violent winds and high waves. They are also calling on people to keep an eye out for frozen water pipes and power outages due to the snow.
Authorities say traffic jams could happen in areas where heavy snow is forecast. Some expressways have already been closed.
Transport ministry officials are urging people to refrain from going out unless it is urgent. Drivers are advised to use winter tires or snow chains.