Dillon Reservoir, sometimes referred to as Lake Dillon, is a fresh water reservoir located in Summit County, Colorado, south of I-70 and bordered by the towns of Frisco, Silverthorne, and Dillon. It is a reservoir for the city of Denver, and its waters are under the control of Denver Water. Popular ski towns are close to the reservoir, including Copper Mountain, Keystone, Arapahoe Basin, and Breckenridge.
During ski season, thousands of people flock to the Dillon Reservoir area. Dillon Reservoir is close to four ski-resorts. Arapahoe Basin is medium sized resort that is approximately ten miles from the lake. Keystone Ski Resort is a large tourist destination that is located approximately five miles away. Breckenridge, which is one of the largest ski resorts in Colorado, is located approximately seven miles from Dillon Reservoir. Copper Mountain is located approximately eight miles from Dillon Reservoir. These resorts stay open all year round.
The reservoir is also a center of attraction for the area. During the winter months, ice fishing and snowmobiling are common activities. For the warmer months, the Dillon Lake marina is open and hundreds of sailboats can be seen docked or sailing. Dillon Reservoir marina hosts many weekend racing regattas and also provides sailboats for rent. The Dillon Yacht Club is based out of the Marina and also hosts many sailing events. Dillon Reservoir is stocked every year with 50,000 rainbow trout by the Colorado Division of Wildlife. Due to Dillon Reservoir's proximity to the towns of Dillon and Frisco, the lake has many lodging, camping, and RV sites.
Dillon averages around 250–300 inches of snow a year. It generally snows from late September to mid-May. There are nearly 300 days of sun during the year, and this keeps the area snow totals lower than the average amount of precipitation the area receives. Almost every day of the year, some sort of precipitation will fall from the sky, with July generally being the wettest month of the year. July is usually the warmest month of the year also with the average high around 73 °F (23 °C). January is the coldest month of the year with the average high being around 31 °F (−1 °C). The average low in July is 40 °F (4 °C), and the average low in January is 2 °F (−17 °C).