Reference data analysis
What the year comparison shows for Lake Thun
Typical low point
557.25 m a.s.l.
February 9
Typical high point
557.82 m a.s.l.
July 11
Typical range
57 cm
Difference between daily medians
In the 1991-2020 reference period, Lake Thun's seasonal median is lowest on February 9 at 557.25 m a.s.l. and highest on July 11 at 557.82 m a.s.l.. The difference between these typical points is 57 cm. This describes the average seasonal cycle, not the largest individual fluctuation.
The 2026 curve currently contains 266 calendar days. On September 23 it shows 557.77 m a.s.l., which is 3 cm below that calendar day's median of 557.80 m a.s.l.. Compared with the same calendar day in 2025, the value is 1 cm higher.
Within the 1991-2020 reference period, the envelope reaches its highest value of 559.25 m a.s.l. on August 24 and its lowest value of 556.96 m a.s.l. on February 16. These are extremes of the displayed reference period, not all-time records.
The analysis uses the water-level series from Spiez. Matching calendar days are compared, and the median is the middle value of the reference years. This classification does not replace flood warnings or local safety information.