What a gauge measures
A gauge is a measuring station at a specific place. Forecasts and measurements describe the water level relative to a height reference. PNP is the local zero point of a gauge, SKN the reference for chart depths and tide tables, NHN the German height system used on land. These reference points lie at different heights depending on the gauge, so water levels can only be compared directly when they use the same reference.
A gauge reading is not a water depth. The height of the sea floor below and the shape of the beach are not part of the gauge reading.
Astronomical tide or water level model?
The astronomical tide prediction shows the regular course resulting from the tidal forces. The BSH points out explicitly that current wind conditions are not taken into account.
An additional water level forecast can respond to the weather. When planning a trip, look at both and check current BSH notices, especially in strong wind or when a storm surge is possible.
Why the beach can be different
Between gauge and beach there can be distance, tidal creeks, sandbanks, harbour entrances and the local coastline. That is why water height and timing on the beach can differ. A map with gauge points is not a complete picture of the current waterline either.
For a visit to the sea, the selected gauge gives orientation about the tide. For swimming, also follow current bathing notices, weather, currents and signs on site.
Reading the water level in the tide display
First choose the place. You then see the tide phase, the height at the reference gauge and the next high or low tide. The height setting lets you choose the zero point shown. When you change the height reference the numbers change; the tide times stay the same.
The North Sea tide map shows the selected gauges and the tide at the chosen time. For a reference place, the display names the gauge used, so it stays clear what the water level refers to.
Always read a water height together with its gauge and height reference. For the actual situation on the beach, local notices and the BSH water level model also matter.
See the tide for your placeFrequently asked questions
Is the gauge reading the water depth?
No. It describes the height of the water surface at a measuring station relative to a height reference. The depth also depends on the sea floor.
Why does the height reference matter?
It defines the zero point from which the height is measured. Without it, water level figures cannot be compared properly.
Does the astronomical tide include wind?
No. The BSH notes in its tide predictions that current wind conditions are not taken into account.