A tide table is a sum of waves. Each wave has a period fixed by the motions of the Moon, the Sun and the Earth. Only its height and its timing belong to the place, and they come from fitting a long record of water levels. This video builds the October 2026 tide at Vlissingen from 55 of these waves.
M2, the main lunar tide, comes every 12 h 25 min and is 171 cm high at Vlissingen. S2, the Sun's tide, comes every 12 hours and adds 49 cm. The two drift in and out of step, which gives spring and neap tides every 14.8 days. N2 follows the Moon's elliptic orbit, and O1 and K1 come once a day because the Moon and the Sun stand north or south of the equator.
The shallow North Sea and Scheldt mouth add overtones. The crest of the tide wave runs faster than its trough, so the curve steepens: the water rises fast after low water, hesitates on the way up and peaks sharply. Further up the river the effect grows. At Antwerp the water rises in about 5 h 30 min and falls in about 6 h 55 min.
With all 55 waves the curve follows the official astronomical tide of Rijkswaterstaat to within 6 cm on average. What remains is the weather: on the night of 25 to 26 October 2026 wind and air pressure raised high water 82 cm above the tide table.
Source: Rijkswaterstaat Waterwebservices, water level and astronomical tide at Vlissingen, January 2025 to October 2026; Antwerp rise and fall times from the Rijkswaterstaat water level forecast. Constituents fitted by least squares
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