FW: 1960 Texas daylight saving time?

Paul Eggert eggert at twinsun.com
Sat Apr 26 01:08:54 UTC 2003

> From: Lisa Borel <lisa.borel at earthlink.net>
> Sent: Thursday, April 24, 2003 8:27 AM

> Can anyone tell me whether Daylight saving time was observed in Houston,
> Texas in 1960?

The best way to answer questions like that is to look into Shanks's
database, which has been converted into online form at:


Just ask for an astrological reading for Houston at whatever time
you're interested in.  Ignore the astrological stuff, and just look at
the UTC offset in the answer.

> From: "Olson, Arthur David (NIH/NCI)" <olsona at dc37a.nci.nih.gov>
> Date: Thu, 24 Apr 2003 09:36:44 -0400
> The time zone database indicates that Houston, Texas (along with the
> bulk of the Central time zone) DID observe DST in 1960.

But the time zone database entry is for Chicago, not Houston.  In the
tz database, regions in the same country are combined if their clock
histories differ only for time stamps before 1970.  This is because I
didn't have the time to do it "right" for all times in recorded history,
and the POSIX epoch of 1970 provided a convenient cutoff.

Chicago and Houston have been the same since 1970, but they differed
before that, so tz's America/Chicago entry is not appropriate for
Houston in 1960.

As it happens, Houston did not observe DST in 1960, according to
Shanks anyway.

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