Crater Lake

Crater Lake has inspired people for hundreds of years. No place else on earth combines a deep, pure lake, so blue in color; sheer surrounding cliffs, almost two thousand feet high; two picturesque islands; and a violent volcanic past. It is a place of immeasurable beauty, and an outstanding outdoor laboratory and classroom.

Crater Lake is located in Southern Oregon on the crest of the Cascade Mountain range, 100 miles (160 km) east of the Pacific Ocean. It lies inside a caldera, or volcanic basin, created when the 12,000 foot (3,660 meter) high Mount Mazama collapsed 7,700 years ago following a large eruption.

Generous amounts of winter snow, averaging 533 inches (1,354 cm) per year, supply the lake with water. There are no inlets or outlets to the lake. Crater Lake, at 1,943 feet (592 meters) deep, is the seventh deepest lake in the world and the deepest in the United States. Evaporation and seepage prevent the lake from becoming any deeper.

Weather plays a dramatic role at Crater Lake National Park. Winter, especially, shapes the landscape; snow generally begins to accumulate each year in October and doesn’t melt in most places until the following June. Summer weather is more predictable, with warm, dry days, blue skies, and cool nights. Nevertheless, there may be days even in August when the lake is completely obscured by clouds and fog. Visitors to Crater Lake National Park should be prepared for any kind of weather, any time of the year.

For the most current park weather forecast, check out the National Weather Service in Medford, Oregon.

Winter Conditions

From October to June, Crater Lake National Park is a snow-covered wilderness. November through April is assuredly snowy with poor
visibility and fair to poor driving conditions, but wonderful skiing and snowshoeing opportunities. With snowfall still lingering on the ground in early July, winter defines Crater Lake National Park more than any other season.

Snowfall averages 533 inches (1,350 cm) annually, and by early spring, it is typical to have ten to fifteen feet (4 meters) of snow on the ground. While snowfall is common in the Cascade Mountains, Crater Lake National Park is one of the snowiest areas in the Northwest where regular records are kept.

The National Park Service began recording weather information at Crater Lake National Park headquarters in 1926. The winter of 1932-1933 still holds the record for total snowfall in a single season, with 879 inches (2,230 cm). In 1950, Crater Lake set a state record for snowfall in a single calendar year, with 903 inches (2,294 cm).
The most snow ever recorded on the ground at Park Headquarters was 21 feet (6.4 meters), on April 3, 1983.

Typical winter temperatures range from a high of about 35 F to an overnight low around 19°F

Why Does Crater Lake Get So Much Snow?

The major weather patterns at Crater Lake National Park originate in the Pacific Ocean. Storm events originate in the north Pacific and build in strength and moisture content over the ocean. Wind patterns at these northerly latitudes move storms from the ocean to the Pacific Northwest. Over 100 inches (250 cm) of rain falls each year on the Oregon Coast. After crossing the Coast Range, storm clouds descend into the Rogue and Willamette Valleys, dropping about 30 inches (76 cm) of rain. As storms move eastward, the high mountains of the Cascade Range push the cool, moist air to elevations over 10,000 feet (3,000 meters) in many places. As the air rises, it cools further. Water vapor in the air condenses to form clouds, and snow crystals form within them. If there is enough moisture in the clouds, the snow begins to fall. If the temperature is warm enough, the snow melts before it reaches the ground and falls as rain. Crater Lake, like all of the Cascade Range, is shaped by its winter snowfall. If you visit the park in summer, try to imagine 16 feet (5 meters) of snow blanketing everything. Then envision spreading phlox covering the roadsides. Without the snow, there would be no phlox, no streams, and ultimately, no Crater Lake.

Summer Conditions

The weather in May and June can vary from warm and sunny to snowy and foggy with poor lake visibility. Temperatures may be as high as 65°F (18°C) or as low as freezing.

July, August, and September are your “best bets” for dry, warmer weather. A typical daytime high temperature during these three months is around 67°F (19°C), but can range from 40°F to 80°F or more (4°C to 27°C). Temperatures cool off rapidly in the evening, with a typical nighttime low around 40°F (4°C), while some nights dip below freezing.

October usually presents cool but sunny days and brings the start of winter snowfall by mid-month.

Summer thunderstorms occur from June through mid-September, bringing dramatic displays of lightning and high winds. Boat tours, guided walks, and evening programs may be canceled if lightning is present in the park.

Did You Know?
Crater Lake was formed when a massive eruption of Mount Mazama 7700 years ago caused the mountain to collapse, leaving a steaming caldera. Centuries of rain and snow filled the caldera creating Crater Lake.