The lake at a glance
- Area (approx.)
- 47.7 km²
- Maximum depth (approx.)
- 217 m
- Reference elevation
- 558 m
- Shore municipalities (selection)
- Thun · Spiez
- Setting
- Bernese Oberland
- Main inflows
- Aare, Kander, Simme
- Outflow
- Aare in Thun
- Regulation
- Mühle and Scherzlig sluices
Elevation is a rounded geographical reference, not the current level. Area and depth may vary with the boundary and survey used.
Editorial responsibility: Patrick Mächler · Mächler Media
Geographical figures checked:
The lake in its landscape
Lake Thun lies at the outlet of the Bernese Oberland. The Aare brings water from Lake Brienz while the Kander and Simme drain extensive Alpine areas. Since the Kander was diverted into the lake in 1714, its catchment has been unusually large relative to lake area, making it more responsive than its calm surface suggests.
The path of the water
Inflows arrive from different valleys and do not always react together. Rain over the Kander can create a different curve from meltwater in the Hasli valley. The Aare leaves through two channels in Thun. Historically, limited outlet capacity allowed major inflows to raise the lake despite open sluices.
Annual cycle and management
Snowmelt and summer rain generally bring more water than winter. The Mühle and Scherzlig sluices regulate outflow, supported by additional flood works. Yet the lake is not an unlimited retention basin. When soils are saturated and several tributaries are high, development over hours and days matters most.
How to read the measurements
Lake elevation describes surface height, while Aare, Kander and Simme discharge measures volume per second. Read the sequence: water arriving from the valleys, the lake's response and what can leave at Thun. Different timestamps can explain an apparent mismatch.
Temperature and depth
This deep Alpine lake can warm quickly at the surface while retaining cold deep water. The Aare from Lake Brienz and the Kander can deliver locally cooler water, redistributed by wind. Surface readings help swimmers; understanding the ecosystem requires depth profiles.
Visiting the lake
Plan a visit using local operators and tourism offices. Check timetables, access and bathing conditions before travelling. Water temperature alone does not indicate bathing-water quality.
Strandbad Thun · Strämu
Lakeside bathing site and pools on Strandbadweg in Thun. Local tourism describes the facilities and access; pool temperature differs from lake water.
Information and directionsRail stations and boat piers are close together at Thun and Interlaken West. At Spiez, allow for the walk from the station down to the lake. BLS lists current connections.
Lake ecosystem condition and hygienic bathing-water quality are different assessments. Check the authority’s area, sampling date and exact site; older samples do not confirm today’s bathing conditions.
Visitor information and links checked:
Gallery
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Checked specialist sources
These sources support the hydrological context. Current readings and timestamps remain on the live page.