Canada here. Winter never, unless we have a rare warm (above -10c/14f) day. Spring as often as I can if/when it's nice enough outside. Summer usually open until the temps get around 27c/80f then closed and the air conditioner on.
I live in a roughly 100 yr old house though, so with all the cracks etc this place tends to self-ventilate anyway.

I'm almost there... moved everything important over to protonmail a few years back, just haven't deleted my 20 yr old gmail account yet because it's tied to an old phone that I still use for apps and taking cat pics, and in case there's something I forgot to change.
I get roughly 1 or two emails a month from places I'm not willing to give my good email to and that's about it.