Half-hour and quarter-hour time zones
Topic: Latitude, Longitude and Time · NCERT: Beyond NCERT
Meaning
Most time zones differ from UTC by whole hours. Some differ by part of an hour, either 30 minutes or 45 minutes. These are half-hour and quarter-hour zones. Countries often choose them so that clock time stays close to the sun's time over their land.
- Half-hour zones: India and Sri Lanka (+5:30), Afghanistan (+4:30), Iran (+3:30) and Myanmar (+6:30).
- Quarter-hour zones: Nepal (+5:45) and the Chatham Islands of New Zealand (+12:45).
Example
At 12 noon in New Delhi (UTC+5:30), it is 12:15 p.m. in Kathmandu (UTC+5:45).
Don't confuse with
- Standard meridian rule: a meridian that is a multiple of 7°30′ gives a whole-hour or half-hour offset. Nepal's +5:45 breaks this pattern.