Lake Thun is a remnant of the former larger glacial lake known as Wendelsee, which covered the entire Bödeli area.
The lake's water level is artificially regulated by a weir at the Aare outflow in the city of Thun.
Subsurface water temperatures remain relatively cool even in mid-summer, typically ranging between 17 and 20 degrees Celsius.
The lake is home to several species of whitefish, which are a primary component of local commercial and recreational fishing.
The northern shore, often called the Riviera of Lake Thun, receives significantly more sun exposure than the southern shore.
The depth of the lake reaches a maximum of 217 meters at its deepest point.
The lake functions as a sediment trap for the Kander River, preventing significant amounts of silt from flowing further downstream into the Aare.
The climate around the lake is influenced by Foehn winds, which can lead to rapid weather changes.
Lake Thun is an alpine lake in the Bernese Oberland region of Switzerland, fed primarily by the Aare and Kander rivers. It sits at an elevation of 558 meters and occupies a basin formed by glacial erosion. The lake is characterized by its deep turquoise water, which is a result of glacial silt sedimentation. It serves as a hub for recreational activities including kayaking, stand-up paddleboarding, and swimming. Several historical castles, including Oberhofen and Spiez, line its perimeter. The lake functions as an integral part of the regional ecosystem and water management system in the canton of Bern. It is bounded by the towns of Thun at its northwestern end and Interlaken at its southeastern end. The surrounding landscape features steep limestone slopes and dense alpine vegetation.
The gardens of Spiez Castle overlooking the lake and the Niesen mountain peak.
Use the BLS boat service to visit multiple lakeside villages in a single day.
Check local wind forecasts before kayaking, as gusts can develop rapidly in the afternoons.
Water temperatures can be cold, so a thin wetsuit is recommended for extended swimming sessions.
Do not attempt to swim across the lake without a support vessel, as boat traffic is frequent.
Boat services operate on a reduced winter schedule; summer service is year-round.
Respect protected nature reserves along the shoreline; no noise pollution; remove all waste.
