Programming programming time

What is UTC?

Definition

UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks. It is the successor to GMT and does not observe daylight saving time. All timezones are defined as offsets from UTC (e.g., EST = UTC-5).

Why It Matters

Storing timestamps in UTC prevents timezone-related bugs — you convert to local time only for display. Databases, servers, and APIs should always use UTC internally. Mixing local times from different timezones is a common source of subtle bugs.

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