Why are there 2 high tides and 2 low tides in a day? Why Two High Tides a Day?
Here is a simpler explanation: Looking down from the North Star, the Earth rotates anticlockwise by about 180 degrees in 12 hours. During that same period of time, the moon travels on its orbit around the earth clockwise by about 180 degrees. The result is that the moon crosses the same earth longitude (but not necessarily the same latitude) every 12 hours, or twice every day. This results in 2 local high tides. The 2 low tides happen between times.
