Station Information

Station ID: 910
Latitude: -34.178611
Longitude: 22.135278
Coastline code: 430
Station code: 81
Time span of data:
Completeness (%): 0
Date of last update: 11 Feb 2021

Green Arrow: Current Station
Yellow Marker: Neighbouring RLR Station
Red Marker: Neighbouring Metric Station

Please note: In many cases, the station position in our database is accurate to only one minute. Thus, the tide gauge may not appear to be on the coast.

Tide Gauge Data

Download metric sea level data. Use only with extreme caution.
NOTE: If some of the data are red in the plots above, the 'flag for attention' is set. Please see the documentation below.

Additional Data Sources (guide to additional data sources)

Fast Delivery Data from UHSLC station 185: hourly and daily
Research Quality Data from UHSLC station 185: hourly and daily

Station Documentation

Link to RLR information.

Documentation added 1991-06-11

Mossel Bay 430/081 RLR(1964) is 12.0m below BM SANZZZ

Documentation added 1996-08-28

For discussions of MSL changes and extreme sea levels around Namibia and South Africa, see: G.B.Brundrit, S.Afr.J.Mar.Sci.,16,9-17,1995 and S.Searson and G.B.Brundrit, S.Afr.J.of Science, 91,579-588,1995. 1958 - 1972 Values based on 8 readings per day for 1978 very suspect and deleted.

Documentation added 2006-07-24

Data for 2000 were supplied by BODC. The values were supplied to BODC via the University of Cape Town and so are not being classed as official.

Documentation added 2006-11-28

1990 data looks highly suspect treat with caution.

Documentation added 2008-02-28

2005 gauge was either non-operational or producing rubbish.

Documentation added 2009-09-24

Heights of chart datum relative to land levelling datum in South Africa and Namibia: Mossel Bay Datum: up to 31st Dec 1978 = -0.761, Datum: 1st Jan 1979 - 31st Dec 1997 = -0.900, Datum: 1st Jan 1998 - 31st Dec 2002 = -1.163, Datum: 1st Jan 2003 onwards = -0.933, Datum is now LAT so unlikely to change.

Documentation added 2009-10-22

SANHO is in the process of re-evaluating and standardising all the tidal station benchmarks. Confirming their accuracy in relation to the existing national benchmark network. This process was carried out at Mossel Bay during Feb. 2007 with new benchmarks installed in May 2007. The new benchmarks are TG Hut LLD +2.7002m New HO2 LLD +3.9022m VT-3 LLD +2.6366m

Documentation added 2012-05-15

Data for Mossel Bay looks high following the installation of the new benchmarks particularly when viewed as the annual rather than the monthly means.

Documentation added 2016-05-10

The apparent spike for August 2015 has been queried with the South African Navy. They are unaware of any specific problems but commented that the region experienced terrible weather during this period. Also, the tide gauge at Mossel is more exposed to open water influences than the other SA gauges which are more protected by the harbours.

Documentation added 2019-11-07

The South African Navy Hydrographic Office (SANHO) are the copyright owners of the Mossel Bay sea level data and must be contacted to request permission to use the data.

Documentation added 2021-02-10

"The South African Hydrographic Office have asked us to remove this record in line with the Hydrographic Act of 2019 (Act No. 35 of 2019) and the South African Spatial Data Infrastructure Act, 2003 (Act No. 54 of 2003). The data can be obtained directly from SANHO (email:

Data Authority

Hydrographic Office
Maritime Headquarters
Private Bag X1
Tokai 7966