First thing Dexter does when he gets outside is stick his face in the biggest snow pile he can find, flip out a chunk with his snout, and snack on some snow :)
Snowball fetch. Snow in Seattle is never more than a few inches deep, not enough to impede a corgi. They follow the snowball, expecting it to bounce like the tennis ball, and when it splats and vanishes, they search in comical befuddlement. They love to catch them in midair.
Spring backcountry nordic skiing has worked well, when the snow is firm enough to support their weight and there aren't many skiers (so ruining the ski tracks is not such a big issue issue). But Al did get a sore paw last time, so I'm trying Pawz booties, and maybe Musher's Secret.
Summertime in the mountains, when they find the first big snowpatch, they often frap on it.
Above timberline in hot sun, they wilt quickly, seeking what little shade they can find; then I try to find snow and make a corgicicle, which they love -- just sit there covered with snow. This is not just for fun-- dogs cannot sweat and they can get heat stroke.