DOT issues final ruling on Indiana time zones

Paul Eggert eggert at CS.UCLA.EDU
Fri Jan 20 05:29:03 UTC 2006

Deborah Goldsmith <goldsmit at> writes:

> In America/Indiana/Knox, on April 2, 2006:
> 1:59:59 EST is followed by 1:00:00 CST (because this location
> switches to Central Time at that moment, and it's Standard Time in
> that zone)
> 1:59:59 CST is followed by 3:00:00 CDT (the normal DST transition)

That may be what the letter of the regulation says (I can't get docket
OST-2005-22114 from right now) but if so, the
regulation is obviously in error.  The intent is that 01:59:59 EST be
followed by 02:00:00 CDT.  Nobody is going to change their clocks
twice in the same morning.

Hence on April 2 there will be an extremely unusual one-hour period
during which there will be five (instead of the usual four) time zones
in the lower 48 states: PST (-0800), MST (-0700), CST (-0600), CDT
(-0500, in a few counties of Indiana), and EDT (-0400).

I'll draft a proposed change along those lines.

It's a bit more complicated than the patch you sent, because
America/Indiana/Indianapolis needs to split into two zones.  Daviess,
Dubois, Knox, Martin, Perry, Pike, and Pulaski counties, which are
currently in the America/Indiana/Indianapolis zone, need their own
zone now that they are moving to central time which means they now
have a new unique time zone history.  Starke county already has its
own zone America/Indiana/Knox, and that entire zone will move to
central time, so it does not need to split.

I think the biggest city in the new zone is Vincennes, so the new zone
should be called America/Indiana/Vincennes.

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