Hi,
As malloc says, weather plays a huge role.
I was on the shinkansen from Tokyo to Nagoya in May and Kyoto to Tokyo in June and both days it was cloudy so did not see it.
However, I had an excellent view flying from HEL to HND prior to landing ( left hand seats)
View of Mt Fuji from JAL HEL-HND 30th april
and also from the sankeien garden in yokohama ( view slightly spoiled by the chemical plant) as well as the Marine tower in yokohama ( afternoon sun problems)
View of Mt Fuji from sankeien garden yokohama ( may 2025)
Regards
TBS