Lake Dillon in the heart of Summit County froze completely on Monday, Jan. 26, close to – but not quite – the latest freeze date ever.
That record still belongs to Jan. 31, 1981, when Summit weathered a warm, dry winter that is eerily similar to this one.
According to the National Weather Service station in Dillon – the official record-keeping station for Summit – the average high temperature in December and January of the 1980-1981 season was 41 degrees Fahrenheit. This year the December-January average is 37 degrees. Most years the average is 5 to 6 degrees colder – right around freezing.
Denver Water has been keeping Dillon Reservoir freeze date records since the reservoir filled in 1966. Data shows it has been freezing later more often.
In the past two years it froze over on the exact same date, Jan. 9, tied for fifth-latest. In the past 15 years, since 2011, the lake has frozen over nine times in January. In the 45 years before that, from 1966 to 2010, it froze over only six times in January.
5 latest freeze dates on Lake Dillon
- Jan. 31, 1981
- Jan. 26, 2026
- Jan. 24, 2018
- Jan. 10, 2013
- TIE Jan. 9, 2024 and 2025
5 earliest freeze dates on Lake Dillon
- Dec. 10, 1972
- Dec. 11, 2005
- Dec. 14, 1971
- Dec. 15, 1985
- Dec. 16, 1992