Reference data analysis
What the year comparison shows for Lake Hallwil
Typical low point
448.50 m a.s.l.
October 3
Typical high point
448.74 m a.s.l.
March 2
Typical range
24 cm
Difference between daily medians
In the 1991-2020 reference period, Lake Hallwil's seasonal median is lowest on October 3 at 448.50 m a.s.l. and highest on March 2 at 448.74 m a.s.l.. The difference between these typical points is 24 cm. This describes the average seasonal cycle, not the largest individual fluctuation.
The 2026 curve currently contains 265 calendar days. On September 22 it shows 448.06 m a.s.l., which is 44 cm below that calendar day's median of 448.51 m a.s.l.. Compared with the same calendar day in 2025, the value is 43 cm lower.
Within the 1991-2020 reference period, the envelope reaches its highest value of 449.17 m a.s.l. on February 25 and its lowest value of 448.12 m a.s.l. on October 26. These are extremes of the displayed reference period, not all-time records.
The analysis uses the water-level series from Meisterschwanden. 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.