Everything about timezones

What is UTC?

UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks and time. It's the successor to GMT (Greenwich Mean Time) and serves as the reference point for all time zones around the world. Unlike local time zones, UTC doesn't change with daylight saving time and provides a consistent worldwide standard.

All time zones are defined as offsets from UTC. For example, Eastern Standard Time (EST) is UTC-5, meaning it's 5 hours behind UTC. When it's noon UTC, it's 7:00 AM in EST.

What is Daylight Saving Time?

Daylight Saving Time (DST) is the practice of advancing clocks during summer months so that evening daylight lasts longer, while sacrificing normal sunrise times. Typically, clocks are adjusted forward by one hour in the spring ("spring forward") and back by one hour in the fall ("fall back").

Not all countries or regions observe DST. For example, most of Arizona in the United States, Hawaii, and many countries near the equator don't use it as seasonal daylight variations are minimal in these areas.

The main purpose of DST is to make better use of daylight during the longer days of summer, which helps conserve energy and may provide more opportunities for evening outdoor activities.