Weather officials in Japan have described this winter season as unusually warm, as it marked the second-highest national average temperature on record.

The Japan Meteorological Agency convened an expert panel on Monday to analyze the weather conditions from December to February.

The panel cited a tendency for warm air to cover Japan this winter. The national average temperature during the period was 1.27 degrees Celsius higher than in the average year, making the season the second warmest since record-keeping began in 1898. The warmest was in 2020.

Agency officials attributed this year's result to global warming. They added that westerlies flowing in high altitudes, including the subtropical jet stream that meandered north near Japan, caused the archipelago to be covered by warm air from the south.

They say another westerly, the polar front jet stream, made only small movements near Japan, preventing cold air from proceeding south.

The panel concluded that the chance of unusually high temperatures would have been extremely low if not for the rise in temperatures due to global warming.

Panel head Nakamura Hisashi, a professor at the University of Tokyo's Research Center for Advanced Science and Technology, said it would be safe to call this winter unusually warm. He added that more similarly warm winters could be in store in the future, depending on weather conditions.