High-Precision Tide Predictions On Your Phone Or Satellite Device

Harmonic & Hydrodynamic Tide Forecasts for Coastal Navigation & Exploration

BoltWX delivers tide predictions and water temperatures directly to your phone or satellite communicator (Garmin inReach®, ZOLEO®, Bivystick). Powered by direct integration with official hydrographic networks in Canada, the United States, and Australia, plus global harmonic coverage worldwide, BoltWX keeps you aware of changing water levels and tidal cycles wherever your coastal travels take you. Works with Apple iPhone®, Google Pixel® and Samsung Galaxy® satellite services.

Official Hydrographic Stations

Direct harmonic calculations from over 1,500 Canadian Hydrographic Service (CHS) stations, hundreds of NOAA CO-OPS stations, and 730+ Australian BOM ports.

Up to 72-Hour Detailed Predictions

Receive consecutive high and low tide times in 24-hour format with precise water level heights in meters or feet and localized water temperature.

Global Ocean Coverage

Global ocean hydrodynamic tidal modeling ensures accurate predictions even in remote international waters and oceanic islands.

Requesting a Tide Prediction via SMS

This feature is available to BoltWX Pro subscribers. Learn more about subscribing here

BoltWX provides dedicated tidal predictions for coastal and oceanic locations worldwide.

Disclaimer: Data is provided for situational awareness only and is not suitable for navigation. Always consult official tide tables, local nautical charts, and marine VHF broadcasts before navigating shallow waters, narrows, or tidal rapids. You agree to use BoltWX forecasts at your own risk (see the BoltWX terms and conditions).

To request a tide prediction, send an SMS message to BoltWX with your access code, the "TIDES" keyword, and your GPS coordinates:

Keyword Description Sample Request
TIDES High and low tide times and heights for the next 48 to 72 hours, plus sea surface water temperature. #ACCESSCODE# TIDES (53.4808, -131.8241)
Looking for Waves & Swell Only?

Get standalone 24-hour or 48-hour nearshore wave height, swell period, and peak gust forecasts.

View Wave Forecast Details →
Need All-in-One Paddle Weather?

Get atmospheric weather, 72-hour tide predictions, and wave forecasts in a single request with KAYAK or KAYAK2DAY.

View Kayaking Details →

Sample Tide Prediction & Translation Breakdown

Here is an example of an SMS tide prediction forecast and a detailed breakdown of each forecast element:

Sample SMS Response Detailed Line-by-Line Breakdown
TIDES CHS (m)
Tu 03:43 1.4 H
Tu 09:15 0.7 L
Tu 14:20 2.1 H
Tu 21:30 0.5 L
We 04:12 1.5 H
Water 14*C

Header: TIDES CHS (m) or TIDES NOAA (ft) indicates the authoritative hydrographic source provider (CHS, NOAA, or BOM) and unit system (meters for (m) or feet for (ft)).

Tide Event Rows: Consecutive high and low astronomical tide events:

  • Tu: Day of the week abbreviation (Tuesday).
  • 03:43: Local predicted tide event time in 24-hour format.
  • 1.4: Water level height relative to local chart datum (1.4 meters or feet).
  • H / L: Tide indicator denoting High tide (H) or Low tide (L).

Water Temperature: Water 14°C (or Water 57°F) reports localized sea surface water temperature.

Official Hydrographic Networks & Harmonic Predictions

BoltWX calls on national hydrographic station databases to calculate exact water levels relative to local chart datum, giving you the most accurate tide forecasts for your location.

Canadian Coastal Waters

Canadian Coastal Waters & Great Lakes

Canadian Hydrographic Service (CHS / IWLS):


  • Integrated Water Level System (IWLS): Direct integration with over 1,500 official Canadian Hydrographic Service tide stations providing official harmonic calculations and chart datum references across British Columbia, Vancouver Island, Haida Gwaii, the Salish Sea, and Atlantic Canada.
  • Continuous Harmonic Calculations: Accounts for complex Pacific fjord resonance and extreme Atlantic semi-diurnal tides (such as the Bay of Fundy).
American Coastal Waters

United States & Alaska Waters

National Oceanic and Atmospheric Administration (NOAA CO-OPS):


  • Center for Operational Oceanographic Products and Services (CO-OPS): Official NOAA harmonic constituent station network across hundreds of coastal tide stations spanning Puget Sound, Washington, Oregon, California, Alaska, the Atlantic Seaboard, Gulf of Mexico, Hawaii, and Caribbean territories.
  • Mean Lower Low Water (MLLW): Direct reference to standard nautical chart datum for US waters.
Australian Coastal Waters

Australian Waters & Ocean Territory

Bureau of Meteorology (BOM) & National Tide Centre:


  • Australian National Tide Centre Network: Official harmonic tide predictions covering over 730 primary and secondary standard ports across NSW, Queensland, Victoria, Tasmania, South Australia, Western Australia, and the Northern Territory.
Global Map Outline

Global Oceans, Caribbean, UK & Europe

Global Hydrodynamic Modeling:


  • Hydrodynamic Tidal Fallback: Global MSL hydrodynamic tidal modeling ensures unbroken coverage for remote offshore points outside regional station coverage.

Tide Predictions FAQ

BoltWX calculates the great-circle distance between your GPS coordinates and thousands of verified tide stations in our CHS, NOAA, and BOM databases. If you are within 20 km of an official station, that station's exact harmonic data is used. If you are outside regional station range or in remote international waters, BoltWX automatically transitions to global hydrodynamic ocean tide models.

Depending on tidal frequency (semi-diurnal vs. diurnal) and satellite message length constraints (160 characters), BoltWX packs between 48 and 72 hours of consecutive high and low tide predictions into the message, ensuring you have visibility over multiple tidal cycles.

BoltWX automatically formats tide heights in meters (e.g. 1.4m) or feet (e.g. 4.6ft) according to the unit preference set in your account profile. You can change your preferred units anytime by editing your profile here.

The header identifies the authoritative hydrographic network used for your prediction: CHS (Canadian Hydrographic Service), NOAA (National Oceanic and Atmospheric Administration), or BOM (Australian Bureau of Meteorology). If no authority is indicated, the system is using global hydrodynamic ocean tide models.

Yes! You can request KAYAK (24-hour) or KAYAK2DAY (48-hour) to automatically receive 3 consecutive SMS messages with a single request: (1) atmospheric weather forecast, (2) 72-hour tide predictions, and (3) wave & wind forecast. You can also request WAVES independently for wind and wave heights. Learn more on the Kayak Forecast page or explore the Waves page.