Definition
Coordinated Universal Time (UTC) is the worldwide standard time reference used in aviation. It is the same instant everywhere on Earth, independent of local time zones or daylight saving adjustments, and is used for flight plans, weather reports, NOTAMs, clearances, and all official aviation timing. UTC is expressed on a 24-hour clock, often written with a 'Z' suffix (for example, 1430Z) and spoken as 'Zulu.'
Plain English
A single global clock that every pilot, controller, and weather service uses, so that everyone is referring to exactly the same moment in time, no matter where they are in the world.
Context Anchor
Seen on charts, flight plans, weather reports, forecasts, and other aviation documents when a time must be understood the same way worldwide.
Derivation
Coordinated' because the time is agreed and synchronized across many national time laboratories. 'Universal' because it is used worldwide as a single reference. The unusual abbreviation 'UTC' was chosen as a compromise between the English (CUT) and French (TUC) word orders, so neither language's version would dominate. Knowing this helps explain why the letters don't match the English phrase.
Why Pilots Care
All flight planning, ATC clearances, and international coordination are referenced to UTC so every pilot operates from the same clock regardless of location or time zone.
Intuition Check
UTC is not local time. If your clock at home changes with your time zone or daylight saving time, that is not UTC; UTC is the shared reference clock used worldwide.
Example Sentence 1
The METAR was issued at 1755Z, so the pilot knew the observation was valid in UTC, not local time.