Half-hour and 45-minute time zones, explained
India, Nepal, Newfoundland and a dozen other places keep clocks that are not a whole number of hours from UTC.
Most of the world keeps a whole number of hours from UTC. A significant minority does not. India, home to roughly one in six people on Earth, is five and a half hours ahead of UTC, and Nepal is five hours and forty-five minutes ahead. If your team includes anyone in these places, "on the hour" in one city is "on the half-hour" or "quarter past" in another.
Every half-hour and quarter-hour offset in use
The table lists every inhabited place whose offset is not a whole number of hours, according to the IANA time zone database (2026c).
| Place | January 2027 | July 2027 | Note |
|---|---|---|---|
| India | UTC+5:30 | UTC+5:30 | About 1.4 billion people, one time zone, no daylight saving. |
| Sri Lanka | UTC+5:30 | UTC+5:30 | Matches India. |
| Nepal | UTC+5:45 | UTC+5:45 | One of only a few quarter-hour offsets anywhere. |
| Iran | UTC+3:30 | UTC+3:30 | No daylight saving since 2022. |
| Afghanistan | UTC+4:30 | UTC+4:30 | |
| Myanmar | UTC+6:30 | UTC+6:30 | |
| Newfoundland, Canada | UTC−3:30 | UTC−2:30 | Observes daylight saving, so it alternates between −3:30 and −2:30. |
| South Australia | UTC+10:30 | UTC+9:30 | Half-hour offset plus daylight saving. |
| Northern Territory, Australia | UTC+9:30 | UTC+9:30 | Half-hour offset, no daylight saving. |
| Lord Howe Island, Australia | UTC+11 | UTC+10:30 | Its daylight saving moves the clock by only 30 minutes. |
| Eucla, Western Australia | UTC+8:45 | UTC+8:45 | An unofficial local time used by a few hundred people. |
| Chatham Islands, New Zealand | UTC+13:45 | UTC+12:45 | Quarter-hour offset with daylight saving. |
| Marquesas Islands, French Polynesia | UTC−9:30 | UTC−9:30 |
Why these offsets exist
Time zones were originally drawn so that clock noon would be close to solar noon. A country that sits between two whole-hour meridians has a choice, and several picked the middle. India adopted UTC+5:30 because it is close to the mean solar time near the centre of the country (82.5°E, close to Mirzapur). Nepal chose UTC+5:45 to be based on the meridian of Mount Gauri Shankar, east of Kathmandu, and to set itself 15 minutes apart from India. Iran, Afghanistan and Myanmar made similar choices for their own central meridians.
The opposite choice is also common. China spans about five geographical time zones but uses one,
UTC+8, everywhere. In the far west, around Ürümqi, the sun can rise after 09:00 in winter, and many residents
informally use "Xinjiang time", two hours behind Beijing. Software reflects this: the IANA database includes a
separate Asia/Urumqi zone at UTC+6, but official business runs on Beijing time.
The extremes of the clock
- The earliest time on Earth is in Kiribati's Line Islands (
Pacific/Kiritimati), at UTC+14. They see each new day first. - The latest inhabited time is UTC−11, in American Samoa (
Pacific/Pago_Pago). Kiritimati and Pago Pago are less than 3,000 km apart, yet their clocks are 25 hours apart. Between midnight and 01:00 in Kiritimati the two places are two calendar dates apart: 00:30 on a Wednesday in Kiritimati is 23:30 on Monday in Pago Pago. - Samoa skipped a day. To align its working week with Australia and New Zealand, Samoa moved across the International Date Line at the end of 2011. Thursday 29 December was followed directly by Saturday 31 December; 30 December 2011 never happened there.
What this means for scheduling
- Watch for the half-hour in every conversion. 09:00 in London in January is 14:45 in Kathmandu (London to Nepal is 5 hours 45 minutes in winter). Mental arithmetic that rounds to whole hours goes wrong here first.
- India does not change its clocks, so its gap to Europe and North America moves by an hour twice a year. See the overlap table for London and New York.
- Pick start times that land cleanly. A meeting at 08:30 New York is 19:00 in Mumbai in winter. A half-hour start on one side can give a round start on the other.
- Let a tool do the arithmetic. The converter and meeting matcher handle half-hour and quarter-hour offsets, and the daylight saving changes on top of them, automatically.