I do understand that tidal forces are caused by de difference of gravitational force between both opposite points of the earth where a bulge is formed. I do understand that a lunar day is ruffle 24 hour and 50 minutes.

What I don’t understand is, why the time difference between equal states of a tide on the next day isn’t 50 minutes.

Example: Today the high tide is at 13:00. Why is the high tide on the next day not at 13:50?

On the charts below we can see, that the time difference is ruffly 1:30 hours. Taking the example above, the high tide would be at 14:30.




I hope my question makes sense to you.


1 Answer 1


The tidal forces from the moon are only a partial driver of oceanic tides. So the timing of the two is not in lockstep. Other drivers like the sun, and interactions with water movements also contribute.

Over a long time, the peaks of the pattern will track with the moon, but these other drivers can delay or advance any particular day's by some amount.

  • $\begingroup$ Thank you very much for your answer. That makes a lot of sense. I waited to confirm your answer because I wated to see if other are also going to reply. $\endgroup$ Sep 9, 2022 at 9:04

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