Visit a national park in the spring, summer, or fall, and you’ll get endless trails, stunning campsites, and mild weather. You’ll also get hordes of other people. Winter is a whole different story, with way-fewer crowds and pristine snow-covered landscapes. With the government finally open again, it’s the perfect time for a visit. Operations and access may be limited due to the season, but the parks below still have plenty to do, from shimmering full-moon hikes to lift-accessed skiing. All you need is a few extra layers.