Lake Washington Ship Canal water level history

Daily records since 2001 · Level today: 20.55 ft

Highest on record

22.02 ft

May 22, 2020

Lowest on record

19.94 ft

Aug 28, 2015

Today

20.55 ft

Oct 21, 2026

Years of data

since 2001

In short

Across 24 complete years, 2015 had the lowest average level (20.59 ft) and 2010 the highest (20.93 ft).

On average the lake is lowest in December (20.01 ft) and highest in May (21.86 ft).

Loading chart…

Measured Normal range for the date (middle 50% of past years)

Years ranked by their lowest daily level.

Year	Average	Low	Low date	High	High date
2026 (290 days)	20.88	19.99	Feb 3	21.99	Apr 28
2025	20.67	19.99	Dec 8	21.98	May 23
2024	20.79	19.96	Jan 10	21.96	Jun 2
2023	20.72	19.97	Feb 7	21.89	May 17
2022	20.80	19.97	Dec 21	21.91	Jun 5
2021	20.76	19.97	Jan 5	21.96	Jun 13
2020	20.86	19.97	Dec 8	22.02	May 22
2019	20.87	19.97	Dec 13	21.98	May 26
2018	20.69	19.97	Jan 28	21.88	May 8
2017	20.79	19.97	Dec 30	21.98	Jun 17
2016	20.70	19.98	Feb 13	21.81	May 3
2015	20.59	19.94	Aug 28	21.91	May 6
2014	20.91	19.98	Jan 10	21.98	Jun 1
2013	20.88	19.98	Jan 27	21.88	Jun 27
2012	20.91	19.98	Dec 3	21.97	Jun 26
2011	20.90	19.98	Jan 14	21.94	Jun 24
2010	20.93	19.98	Jan 5	21.92	May 21
2009	20.79	19.97	Dec 24	21.90	Jun 5
2008	20.92	19.96	Dec 19	21.94	Jun 6
2007	20.86	19.98	Dec 23	21.91	May 23
2006	20.79	19.97	Jan 11	21.95	May 18
2005	20.84	19.97	Feb 2	21.94	May 31
2004	20.87	19.96	Jan 3	21.99	Apr 27
2003	20.80	19.96	Jan 4	21.92	May 26
2002	20.81	19.95	Jan 26	21.95	Jun 21
2001 (175 days)	20.80	19.98	Dec 17	21.71	Jul 10

Levels in feet. Partial years show the number of days with data.

Month	Average	Lowest	Highest
January	20.02	19.95	20.66
February	20.17	19.97	20.76
March	20.89	20.34	21.70
April	21.61	21.10	21.99
May	21.86	21.60	22.02
June	21.77	21.02	21.98
July	21.38	20.42	21.95
August	20.80	19.94	21.57
September	20.47	19.98	21.37
October	20.52	20.02	21.29
November	20.23	19.99	20.58
December	20.01	19.96	20.66

Daily levels as CSV (9,231 rows; credit the original agencies listed below)