Frequently Asked Questions
UTC (Coordinated Universal Time) is the world's primary time standard. All time zones are expressed as offsets from UTC — for example, UTC+9 is 9 hours ahead (used by Japan), and UTC−5 is 5 hours behind (used by Eastern US in winter). UTC does not observe daylight saving time.
Most time zones are offset by a whole number of hours from UTC, but some countries use unusual offsets for geographic or political reasons. India uses UTC+5:30, Iran uses UTC+3:30, Nepal uses UTC+5:45, and Australia's Northern Territory uses UTC+9:30. These ensure that solar noon is closer to clock noon for their regions.
France spans the most time zones (12) due to its overseas territories. Russia has 11 time zones. The United States has 6 standard time zones (9 if you include territories). China officially uses only 1 time zone (UTC+8) despite spanning 5 geographic zones, which means sunrise in the western regions can occur after 10 AM local time.