Eli5:How come some days will have two high tides and two low tides whereas other days have one high tide and two low tides?

Question

Eli5:How come some days will have two high tides and two low tides whereas other days have one high tide and two low tides?

In: 0

Answer 1

The moon causes the tide by “pulling the water” towards it in a bulge with a second bulge on the opposite side of the earth. The earth then spins in this uneven bulging mass of water with one full rotation every 24hrs. The moon’s orbit 24hrs and 50mins means the bulges are moving at a slightly slower speed then the earth’s spin. Local tides can be slowed down if the bulge has to squeeze through narrow areas like the Gibraltar straits or the English channel. Buy like others have said they are regular but sometimes just the wrong side of midnight to be counted.