Japan pays fastidiously detailed attention to the seasons.
The text books here have a mantra of Japan being special because it has four season - which irritates a lot of foreigners because many other places also have four seasons. I have heard before, unsubstantiated, that the preoccupation of having four seasons comes in the 1800s when Japan is endeavouring to ''civilized and enlightened'' which meant Europeanised rather than Asian (where 4 seasons is not the norm).
The theory of 4 seasons being relatively new seems plausible, in part based on the minute detail of seasonal markers, that suggest to me that in all likelihood Japan had more seasons in the past.
23rd of October is marked as the day of the first frost of Honshu Island. (occurring in the northernmost Aomori prefecture. This year the actual first frost was on the 22nd - if my hearing of NHK news was correct. Nagano prefecture - a mountain prefecture - 26th is the marker date for the first frost, though the heavy rain we are having today suggests they probably didn't. Tokyo apparently does not get it's frost until a month later.
The weather has shifted markedly since the first frost day, significantly colder. bbbbrrrrr
Bring out the down! I am not made for winter.