I'm sure u could find legit #'s for all resorts somewhere on the web.
but in utah its all over the place man. it could be like 15F all month and dumping. or it could be 45 during the day and melting. but usually I'd say february is sick, last year it was awesome. there was about two weeks where it was killer last year at alta, around presidents day, goooood snow. but its hard to say man, u can't predict it. thats why I live here. but for the most part I would say its cold, below freezing, usually not below 0F, which is kind of nice. and hopefully stomry as hell.
as far as jackson: for the most part the same I think, but alot colder sometimes, wyoming gets some chilly shit sometimes. but I'm sure its got a nice range, just a colder average.
and as far as terrain goes, there is crazy shit at jackson and the bird. but jackson I would say has some really gnarly big mountain and steeps. like the good tgr shit. but on the other hand bird/alta are insane too. but I think jackson is just one more step up. but both of them offer all types of terrain, suited for any average skier. and they both have terrain where any skier can step up thier game.
both have alot of sick BC, specially utah, considering what I see out my window.