The Observatory launches the “Coastal Sea Level (Trial)” web page

29 December 2025

The Hong Kong Observatory launches the “Coastal Sea Level (Trial)” webpage today (29 December) with enhanced tidal information. The new webpage not only provides the recorded water levels at 14 tide stations along the coast of Hong Kong, but also features the total water level forecast for the next 12 hours, together with a likely range of the prediction indicating its uncertainty. According to past statistics, the probability of the actual water level falling within the predicted likely range is about 70%.

The total water level forecast incorporates astronomical tide prediction and the anomalies brought about by meteorological factors such as monsoons or storm surges. Water level observations are updated every five minutes. The “Realtime Tides” charts on the “MyObservatory” mobile app will also be upgraded to “Coastal Sea Level” containing total water level observation and forecast in the future update.

The new water level forecast information keeps members of the public informed of the potential changes in coastal sea levels and facilitates them to plan for activities near the shore. Residents in low-lying coastal areas can also take appropriate precautionary measures in advance if there is a risk of seawater inundation associated with the high water level forecast.

Layout of the webpage for coastal sea level (trial)