There is around 12 hours and 25 minutes between two high tides.
Spring Tides & Neap Tides
There are two types of tides: spring tides and neap tides. Spring tides occur when the Sun, Earth, and Moon are lined up in almost a strait line, in other words during full moon and new moon. At times like this the moon's gravitational force is combined with the sun's gravitational force, creating very high tides. Spring tides has nothing to do with spring time. Neap tides occur when the Sun and the Moon work at right angles, in other words during the moon's quarter phases. At times like this, the Sun and the Moon's gravity work against each other, creating low tides.
Low Tides and High Tides
A low tide(left) is when the water level is at its lowest level of the day. Low tides occur twice a day. A high tide(right) happens when the water level is at its highest level of the day. High tides just like low tides also occur twice a day.
The largest tides in the world occur in the Bay of Fundy in Halifax, Canada. Each day, 100 billion tonnes of seawater comes in and out of the Bay of Fundy! The difference between low tides and high tides can vary up to 16 meters because of the bay's shape.
Near the equator, the tides are weakest. That's because the tidal bulge of the Moon follows the path on the earth's surface, which crosses with the orbital plane of the Moon. This plane is about 23 degrees to the equatorial plane of the earth. This results in the fact that near the equator, the difference between high tide and low tide is relatively small compared to other latitudes.
Cause of Lunar Tides
Lunar tides are caused by the interactions between the Sun and the Moon. Tides are also caused by other geographical features.