Japan's average temperature so far this year is 0.74 degrees higher than the temperature for an average year, putting 2000 on course to become the fifth-warmest year in the 100 years that records have been kept, according to the Meteorological Agency.
The agency said the Japanese archipelago as a whole experienced higher-than-normal temperatures throughout the year -- except between February and April.
The southeastern islands experienced higher temperatures in January and from October to this month.
The agency said Japan and the world have been experiencing a warming trend since around 1990. The agency added that the world could be experiencing a period of warmer temperatures that appears in cycles of several dozens of years.
But it said the warmer weather could continue due to the effect of greenhouse gas emissions.
The world is on course for experiencing its third-warmest year with an average annual temperature so far 0.57 degree higher than the average recorded between 1961 and 1990.