Here's why:

* Gravitational Pull: The Moon's gravitational pull is the primary force responsible for tides. Even though the Sun is much larger, the Moon is significantly closer to Earth, making its gravitational influence on the oceans stronger.

* Tidal Bulges: The Moon's gravity pulls water on the side of Earth facing the Moon, creating a bulge of water. A corresponding bulge forms on the opposite side of the Earth due to inertia. These bulges are what we experience as high tides.

* Moon's Orbit: As the Moon orbits the Earth, these tidal bulges move with it, causing high and low tides to occur in regular cycles.

While the Sun does have an influence on tides (especially during spring tides), the Moon's gravitational pull is significantly stronger, making it the dominant factor in tidal patterns.