>>990691Flying Witch is a nice comfy anime set pretty much in summer, I can't recall any winter episodes or anything like that.
Kamichu does have a winter episode or two (I think about Christmas and New Years) but from what I recall they mostly deal with things in the Summer since it's about them being at school. Has a pretty sunny atmosphere about it.
You're Under Arrest TV + OVA is pretty much set throughout summer or so, can't recall any winter episodes. Hell, one OVA is set on a sweltering summer day where the MC's have to divert traffic at the beach.
Taisho Baseball Girls was another, but it's been a while since I've watched it so I might not remember it fully.
I imagine you've seen the movie Summer Wars, right?
