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Comment by cuu508 | Hacker News Reader

Apparently there are some timezones (Cuba, Egypt, Lebanon) where DST change happens at midnight, so, also watch out for that!

https://mas.to/@mpirnat/115395859892135002

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Wait, are there timezones where the DST change doesn't happen at midnight? That's news to me.

Now this article makes sense to me; I was wondering what made 02:00 and 03:00 special, since the DST changes would be from 00:00 to 01:00 and from 00:00 to 23:00, as I'm used to since childhood here in Brazil. Perhaps some other countries change DST from 02:00 to 03:00 and vice versa?

In the UK we move forward at 1am and they go backward at 2am. Doing it at midnight adds the extra complexity that now the day is different. Doing it in the early morning doesn't change the day.

My guess is that in the US they do the same but shifted by one.

All of Europe changes from 02:00 to 03:00

Better to think of it that it changes at 01:00 UTC, which takes care of the parts of Europe that are 2 or 3 hours ahead (instead of CET's 1 or 2), and the UK going "forward at 1 and back at 2"

"Europe DST changes at 01:00 UTC" - much simpler ;)

In the United States, we go from 1:59am to 3:00am in March, and from 1:59am to 1:00am in November for our time change.

Most timezones change time when there's a minimal amount of people working, as these people would have to work an extra hour, and doing it at around 3am is the most reasonable from that point of view.

There are TZ rules that do all sorts of wild things.

Leading to my favourite web comic of all time.

https://www.monkeyuser.com/2018/going-global/

Monkey User is always entertaining.

Brazil not only had DST at midnight, but until 2008 they also had no standard rule for when DST would begin and end, setting the dates by decree often just a few weeks in advance.

Kind of funny that it went from a Ramadan model to an Easter-post-computus model

https://en.wikipedia.org/wiki/Ramadan#Beginning https://en.wikipedia.org/wiki/Date_of_Easter

Is there any other person other than Arthur David Olson who needed an RFC written to cover their retirement?

https://www.rfc-editor.org/rfc/rfc6557.html

Jon Postel, the original RFC Editor and IANA: https://www.rfc-editor.org/rfc/rfc2468

https://www.timeanddate.com/time/time-zones-interesting.html

I wonder how on earth do you deal with a 30 or 45 minute offset in real life

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