Two days after central Tokyo experienced unseasonal 17 deg C heat, a rare snow day yesterday caused snarls to its transport networks.
The cold snap caused 157 domestic flights to and from Tokyo's Haneda and Narita Airports to be cancelled, a tally by public broadcaster NHK showed as of 7pm.
More than 20,000 travellers were affected. Delays of up to two hours were reported at Haneda Airport, while at least one runway was closed at any one time at Narita Airport for snow clearance.
While Tokyo usually experiences snow at least once every winter, it typically melts quickly rather than accumulate on the ground.
The Japan Meteorological Agency had said earlier that a strong cold front and a passing low-pressure system might combine to dump snow across wide areas of Japan throughout yesterday. But it lifted heavy snow warnings by the early afternoon yesterday.
The agency has predicted that as much as 5cm of snow may accumulate in central Tokyo's 23 wards by 6am today.
Throughout the Kanto region, which encompasses the Greater Tokyo area, 10cm of snow was expected in Tochigi, 8cm in Ibaraki and Chiba, and 5cm in Kanagawa, south of Tokyo.
As at 6pm yesterday, 16 people were sent to hospital after falling on slippery roads, NHK said.
The snow comes two days after the unseasonal heat last Thursday, which the agency said was typical of mid-April and about 10 deg C higher than the average temperature for this month. The warmth, the agency said, was due to a rising warm air front from the south.
It urged people to monitor closely transport disruptions as train services have typically been curtailed by delays on heavy snow days.
Meanwhile, Japan's northernmost Hokkaido shivered through its coldest day in 40 years on Friday, when its capital, Sapporo, recorded a daytime high of minus 10.1 deg C.
It was the first time in four decades that the mercury had breached minus 10 deg C, and news pictures showed visitors to the Sapporo Snow Festival wrapping themselves up in thick jackets to protect themselves from the biting winds as "feels like" temperatures plunged to about minus 20 deg C.
The weather agency said this was due to a cold air mass with a record low temperature of minus 24.4 deg C that was flowing in over Sapporo at an altitude of 1,500m.
Other Hokkaido municipalities also saw frigid conditions. In Rikubetsu town, the mercury plunged to minus 31.8 deg C, the first time this winter that temperatures have fallen below minus 30 deg C.