I’ve been a civil time geek for a while, and I follow an e-mail list relating to IANA’s tz database.  It looks like the tz-art.html file in the next release will contain a link to Wednesday’s xkcd. 😎

There’s been a lot of discussion on the list about the proposed “permanent daylight saving time” law that just passed in the U.S. House of Representatives.  It sounds simple:  the proposed law doesn’t change the time zone names; it just changes the offsets from UTC and makes them permanent.  For example, “eastern standard time” would become UTC−4:00 year-round.  But states would be allowed to opt out, so for example, Hawaii could keep its UTC−10:00.

So what if Arizona decides to keep its UTC−7:00 year-round but doesn’t call it Pacific standard time?  Mountain standard time would mean different things in tz’s time zones, America/Phoenix (Arizona except Navajo Nation) and America/Denver (generic mountain time).

Furthermore, it turns out that there’s lots of legacy code out there that hard-codes offsets to abbreviations like “MST”.  All that code happens to work at present; but it’s been wrong for decades and so will likely stay wrong.

I’ll bring the popcorn. 😎