Many leaves have not yet turned red in flat areas across eastern and western Japan - an abnormal situation for late autumn.
The delay has been attributed to temperatures being 1 C warmer or more compared to the average November, which experts said is the result of global warming.
At some sightseeing spots that are famous for autumn colors, there have been moves to adjust the times for planned events because the maple leaves are still green.
"We need to consider extending the term for lighting up trees," said Hoten Sato, general affairs section chief at the Takahata-Fudoson Kongoji temple in Hino, western Tokyo. The temple planned to light up about 1,300 maple trees at its premises from Nov. 18 to Nov. 30 for a maple festival. However, because only some of the maple leaves have turned red, the temple is considering extending the period into December.
At the Sankeien Garden in Yokohama, which is located in an area of Kanto where the autumn leaves front arrives last, the leaves on its famous maple trees also have yet to change colour. The garden's management office is consequently considering extending the time that it opens its promenade to the public.
Rikugien Gardens in Tokyo's Bunkyo Ward that attract about 200,000 people for leaf viewing every autumn, lights up trees from Nov. 19. However, many of the leaves are still green, causing concern that the gardens will lose visitors.
According to the Japan Meteorological Agency, the autumn foliage season has recently been arriving later. In 1953, the leaves on a sample maple tree in Tokyo changed colour on Nov. 8. However, in the 1980s, this often occurred in late November and sometimes in early December.
In order to change into beautiful colors, leaves need conditions including extreme temperature differences and lots of sunshine. However, according to the agency, the average temperature in eastern Japan in early November this year was 1.4 C higher than what is usual, while in the west it was 1.6 degrees higher.
According to a one-month weather forecast through Dec. 20 announced by the agency on Thursday, the temperature will remain higher than in usual years in both eastern and western Japan.
One of the causes for the high temperatures is the El Nino weather phenomenon, which the World Meteorological Organisation pointed out is affecting the largest area on record.
Warmer winters in Japan have been attributed to the phenomenon. Hideaki Oba, professor emeritus at the University of Tokyo and an expert on botany, pointed out that a difference of 1 C will significantly affect the time that leaves change colour. "In addition to global warming, the delay of autumn tints [on leaves] has also been affected by the El Nino phenomenon," Oba said.