The standard trope when talking about timezones is to rattle off falsehoods programmers believe about them. These lists are only somewhat enlightening – it’s really hard to figure out what truth is just from the contours of falsehood.

So here’s an alternative approach. I’m gonna show you some weird timezones. In fact, the weirdest timezones. They’re each about as weird as timezones are allowed to get in some way.

Asia/Kathmandu has a weird offset from UTC Africa/Casablanca doesn’t fit into the timezone model cleanly, so it’s hard-coded America/Nuuk does daylight savings at -01:00 (yes, with a negative) and Africa/Cairo and America/Santiago do it at 24 o’clock (not 0 o’clock) Australia/Lord_Howe, population 382 and some notable stick bugs, has the weirdest daylight savings rule To learn how their weirdness is represented in software, we’ll look at the raw timezone files that all software ultimately relies on. From there, two things will become clear:

Yeah, this stuff is weird But only finitely so, because ultimately a computer’s gotta implement them But first, an aside on the calendar.

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