What qualifies as a sunset?
Quick Answer: A sunset is when the top edge of the Sun disappears below the horizon in the west. It marks the end of the day’s sunlight and the start of twilight.
Sunset happens because the Earth rotates, making the Sun appear to move downward in the sky. When the Sun's upper limb crosses the horizon line, that moment is called sunset.
The exact time of sunset changes daily and depends on your location, date, and local terrain. After sunset, the sky gradually darkens until night takes over.