Tides, Weather & Ocean Data
Free tide times, weather forecasts, wave conditions and moon phases for over 17,000 ports in 180+ countries. Plus a powerful REST API for developers.
Tides & weather for everyone
Coastal explorers
Free tide times, weather forecasts, moon phases and sea conditions for over 17,000 ports worldwide. Perfect for fishing, surfing, sailing and beach activities.
Find your portDevelopers & apps
7 REST API endpoints for tides, weather, waves, sun & moon data. Free API key, clean JSON, 99.9% uptime. Built for your next app.
Get API keyPopular tide stations
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Why TidesAtlas?
Accurate tide predictions
Precise tide times and heights for up to 10 days, powered by the FES2022 harmonic model.
Weather & ocean data
Live weather, wave forecasts, sun & moon data alongside tide predictions for every port.
Worldwide coverage
Over 17,000 tide stations across 180+ countries, from major ports to remote coastlines.
Powerful API for developers
Integrate tides, weather, waves and astronomy data into your apps with our simple REST API.
Tides
High & low water times, heights, coefficients for 17,000+ stations
Weather
Temperature, wind, precipitation, UV index, hourly & daily forecasts
Waves & marine
Wave height, swell, sea state, wind waves from Copernicus/ECMWF models
All countries
Europe
North America
South America
Africa
Asia
Oceania
Other
About our data
TidesAtlas combines four complementary data sources: the TICON-4 harmonic database (3,000+ stations, up to 60 constituents), NOAA reference stations (1,075 US stations, 37 constituents), the FES2022 global ocean model (13,000+ stations, 8 major constituents), and real-time sea level observations from REFMAR/SHOM (~100 French tide gauges, Licence Etalab 2.0). Together they cover 17,400+ stations in 188 countries. Tidal coefficients for France are sourced from official SHOM data. All predictions are updated daily.
Multi-source prediction engine
Our tide predictions are computed from three sources: TICON-4 (3,000+ stations, up to 60 constituents), NOAA (1,075 US reference stations, 37 constituents), and FES2022 (13,000+ stations, 8 major constituents). FES2022 is developed by LEGOS/CNES and validated against satellite altimetry and in-situ measurements. For ~100 French stations, real-time sea level observations from the REFMAR/SHOM tide gauge network are also displayed alongside predictions.
Verified data sources
Tide gauge data is sourced from national hydrographic offices worldwide: SHOM (France), NOAA (United States), UKHO (United Kingdom), BOM (Australia), CHS (Canada), and many others. Each station provides harmonic constants calibrated from years of continuous measurements. Additionally, real-time observations from the REFMAR network (operated by SHOM) provide live sea level data for ~100 French tide gauges under Licence Etalab 2.0.
Daily updates
Predictions are regenerated daily to ensure accuracy. For French ports, official SHOM tidal coefficients are integrated, providing the reference standard used by maritime authorities, fishermen, and coastal professionals.
Frequently asked questions
What are tides?
Tides are the periodic rise and fall of sea levels caused by the gravitational forces of the Moon and Sun, combined with the rotation of the Earth. They follow predictable cycles that can be calculated years in advance using harmonic analysis.
How often do tides occur?
Most coastal locations experience two high tides and two low tides each day (semidiurnal tides), approximately every 12 hours and 25 minutes. Some locations have only one tidal cycle per day (diurnal tides) or mixed patterns.
What is a tidal coefficient?
A tidal coefficient is a dimensionless number (typically 20 to 120) that indicates the amplitude of a tide relative to the average. Higher coefficients mean greater tidal range (spring tides), while lower coefficients indicate smaller tidal range (neap tides). Coefficients above 100 indicate exceptional tides.
How accurate are tide predictions?
Our predictions use the FES2022 harmonic model with data from thousands of tidal stations worldwide. Accuracy is typically within 10-15 cm for height and 5-10 minutes for timing. For French stations, we also display real-time observations from REFMAR/SHOM tide gauges, allowing you to compare predicted vs actual sea levels and see storm surges in real time.