In Tokyo the average number of days with sub-freezing temperatures decreased by 95 percent over the course of the 20th century, reflecting the advance of global warming, according to the Meteorological Agency.

Newly released data show that in the first 10 years of the century, there were an average of 61.7 subzero days in the city each year. By the 1990s, however, that number had fallen to just 3.2.

In contrast, the number of nights per year in which Tokyo's temperatures remained above 25 came to an average of 29.6 between 1991 and 2000, up from 0.7 nights between 1901-1910, the agency said.