I've been playing ACNH for about 30 mins or less almost every day this summer and, while repetitive, it's been a very nice way to start my day. However, with September beginning, the grass getting lighter, Nook's Cranny decorating appropriately, and villagers starting to talk about the crisper weather, I can't wait for another fall and winter in ACNH. For me, September-December is the best time to play the game because of the changing scenery, holidays, and items you can use to decorate your island.
The fall colors are so pretty. And the few times it snows in December (before the trees and terrain turn to snow) is beautiful.