I hear "Japan has four seasons" a lot living there, but I don't get it. It definitely has summer. Leaves take 8 months to gradually fall from trees (if they fall at all) before summer starts again. There's no snow. And obviously there's no snowmelt or sudden greening in the spring.
You might be able to make the claim if your four seasons are "Summer, Typhoon season, Rainy season, Not-summer".
Obsessing over having 4 seasons is a theme that comes up in several cultures and I believe it is probably an ancient relic from when agrarianism was a nascent lifestyle upon which to base a civilization. Some nomadic cultures are similarly obsessed with the 4 cardinal directions.
There is snow in Japan close enough pretty much everywhere in the country if you are willing to drive a bit. For example, there's not much snow in Osaka but a lot in Kyoto and a lot around Nagoya, which are close enough.
You might be able to make the claim if your four seasons are "Summer, Typhoon season, Rainy season, Not-summer".