The Earth turns once in 24 hours, so the Sun appears to cross the sky westward at 15° an hour. Press Play and watch the point where the Sun is overhead step west, one hour mark at a time.

Press Play, or move the time. The marks show where the Sun is overhead at each whole hour.

Time at Greenwich (UT): 09:00
Sun overhead at: E 046°52.0'
Moves west each hour: 15°

360° in 24 hours is 15° an hour: 1° every 4 minutes, 1′ every 4 seconds.

Time and arc are two ways of saying the same thing:

1 hour	15°
4 minutes	1°
1 minute	15′
4 seconds	1′

2h 30m is 2.5 hours, so the Sun moves 37°30.0′. In the other direction, 37°45.0′ takes 2h 31m 00s.

The Sun moves 15° an hour