What does a time zone "offset" mean?
Quick Answer: A time zone offset is the difference in hours and minutes between a local time and Coordinated Universal Time (UTC). It tells you how many hours ahead or behind a place is from UTC.
Every place on Earth sets its clock based on UTC, the global time standard. The offset shows how much you add or subtract from UTC to get the local time.
For example, if a time zone has an offset of +3:00, it means the local time is 3 hours ahead of UTC. If it's -5:00, local time is 5 hours behind UTC.