Once the sun reaches the horizon, it takes around two to three minutes to set. This depends on various variables, including latitude, season, and atmospheric density.
The sun appears to move across the sky at a rate of 1 degree each 5.6 minutes as the planet spins. The diameter of the sun’s disc is approximately 0.5 degrees. However, latitude has a significant role in this; the closer one gets to the equator, the more directly and rapidly the sun sets. The thickness of the atmosphere through which the sun’s light must travel near the horizon also affects the duration of the sun’s descent. At latitudes farther from the equator, sunlight must travel through a greater amount of atmosphere and hence appears to move more slowly.