given - lost in translation
we know that when the band was just uenoyama, haru and kaji the band was named "the seasons" because they all have the kanjis for the seasons in their names, but here's the breakdown :
uenoyama : 立夏 (rikka - given name) meaning first day of summer
haruki : 中山 (haruki) ; 中 (haru) meaning spring
kaji : 秋彦 (akihiko) ; 秋 (aki) meaning autumn
they could've kept "the seasons" with the inclusion of mafuyu, too, since
真冬 (mafuyu) -> 真 (ma) - true ; 冬 (fuyu) - winter
but did you also know that pain is endless 🥲 because
although yuki's name uses the kanji 由紀 (yu - reason, cause ; ki - chronicle) it is also a homophone for 雪 (yuuki - snow)
so
"just like the snow in the shade that hasn't completely melted, i continue on with these feelings inside me" (first line of fuyunohanashi / a winter story / mafuyu's song)
winter can exist without the snow but snow can't exist without winter ദ്ദി ꒦ິ꒳꒦ິ )
i do not claim to be a translator - lost in translation disclaimer
