A zone offset that is not a whole number of hours — India, Iran, Nepal and others.
Not every time zone sits on a whole hour. India and Sri Lanka keep UTC+05:30, Iran +03:30, Afghanistan +04:30, Myanmar +06:30. Nepal keeps UTC+05:45, a quarter-hour offset, fifteen minutes ahead of India.
These are legislated choices, frequently made to sit between two neighbours or to place solar noon more conveniently for a country's centre. They are not historical curiosities: India alone is well over a billion people on a half-hour offset.
For software the consequence is narrow and important. Any code that stores an offset as an integer number of hours, or that renders a zone as a whole number, is wrong for a substantial fraction of the world's population.
Three legislated offsets that are not whole hours, all verified from the IANA database for the same day in 2027.
| 🇮🇳 | Monday 15 March 2027India | UTC+05:30One zone for the whole country, on a half-hour offset. |
| 🇳🇵 | Monday 15 March 2027Nepal | UTC+05:45A quarter-hour offset — fifteen minutes ahead of India. |
| 🇮🇷 | Monday 15 March 2027Iran | UTC+03:30Half an hour, and Iran abandoned daylight saving in 2022. |
A half-hour offset is one kind of UTC offset, called out because integer-hour assumptions are common and wrong.
See also utc offset · time zone · iana time zone
We hold this as derived from the IANA zone. See what we hold.