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volemo • yesterday at 6:49 AM • 2 replies • view on HN

I don’t understand this. What practical difference does it make making the time to round to the nearest quarter of an hour instead of the nearest hour? Personally, I don’t care if noon (sun is in zenith) happens half an hour before 12:00 or half an hour after.

Why do such time zones exist?

Replies

johnisgood • yesterday at 9:45 PM

Oh by the way, check this out, this is one of the news in 2025b tzdata:

  # From Roozbeh Pournader (2025-03-18):
  # ... the exact time of Iran's transition from +0400 to +0330 ... was Friday
  # 1357/8/19 AP=1978-11-10. Here's a newspaper clip from the Ettela'at
  # newspaper, dated 1357/8/14 AP=1978-11-05, translated from Persian
  # (at https://w.wiki/DUEY):
  # Following the government's decision about returning the official time
  # to the previous status, the spokesperson for the Ministry of Energy
  # announced today: At the hour 24 of Friday 19th of Aban (=1978-11-10),
  # the country's time will be pulled back half an hour.
From https://github.com/eggert/tz/blob/main/asia#L1503.

Pretty sure we can find a lot more oddities that are way worse.

johnisgood • yesterday at 7:23 AM

Well, I do not know the answer to that, my guess is that it is for historical, political, geographical, and socio-economic reasons.

For example in terms of India, they had two timezones before they adopted a compromise: UTC+5:30.

Nepal uses UTC+5:45, partly to distinguish itself from Indian Standard Time, reinforcing national identity.

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