Global coordination requires agreement on time standards, maintained by international bodies and navigated carefully in software and business.
UTC - The Global Standard
Coordinated Universal Time (UTC) succeeded GMT as the global time standard. It is based on atomic clocks, never observes DST, and serves as the reference for all time zone offsets. The abbreviation UTC is a compromise between English (CUT) and French (TUC).
Time Authorities
The International Bureau of Weights and Measures (BIPM) in Paris maintains UTC based on atomic clocks and coordinates with national time services. Major national services include NIST (US) at time.gov, NPL (UK), PTB (Germany), and NICT (Japan).
Leap Seconds and Politics
Earths irregular rotation requires occasional leap seconds to keep UTC aligned with solar time. About 27 have been added since 1972, usually on December 31 or June 30. Time zones are also political: China uses one zone despite spanning five, Spain is geographically in the wrong zone, and countries periodically change DST policies.
Coordinating Global Teams
For global meetings, use a shared reference timezone (often UTC), tools like World Time Buddy, and explicit notation like "3pm EST (8pm UTC)". Common overlap windows: US East + Europe in morning US/afternoon EU; Europe + Asia in afternoon EU/evening Asia. US West + Asia have almost opposite schedules.