About tides, currents, and water levels

Learn about tides and currents in Canada and the history of tidal measurements.

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Services and information

Tides and currents in Canada

About tides and currents, including their causes and how we use their data.

Notices and important messages

Notices on digital services and water level gauges.



List of tidal terms and expressions, and acronym meanings.


Vertical datum chart references

About the vertical datum reference on navigational charts.


Tidal phenomena

Tides and tidal streams, shallow water effects and non-tidal influences.

History of tidal measurements

Background on tidal, current and water level surveying.


What we are doing


CHS Digital Transformation Initiative

CHS Digital Transformation Initiative

At the Canadian Hydrographic Service, innovation is a guiding principle for the bold digital transformation initiative now underway.

NONNA Version 3.0 Release

NONNA Version 3.0 Release

Client suggested enhancements have been implemented to the CHS NONNA Data Portal including migration to chart datum and enhanced tools for selecting and downloading large geographic areas.

2024 Tide Tables Available Now

2024 Tide Tables Available Now

Download your 2024 Canadian Tide and Current Tables now to help navigate safely through Canadian waters.