Welcome to Crater Lake National Park
The park's popular south entrance is open year-round and provides access to Rim Village and Mazama Village, as well as the park headquarters at the Steel Visitors Center. In winter you can only go up to the lake's rim and back down the same way; no other roads are plowed. The north entrance is only open from early June to late October, depending on snowfall.
It's best to top up your gas tank before arriving at Crater Lake. There's reasonably priced gas at Mazama Village (summertime only); the closest pumps otherwise are in Prospect, Diamond Lake and Fort Klamath.
Summer is often cold and windy, so dress warmly.