[tz] Unfortunate time zone names in the United States

Fred Gleason fredg at paravelsystems.com
Fri Mar 18 14:40:51 UTC 2022

On Mar 17, 2022, at 19:14, Paul Eggert via tz <tz at iana.org> wrote:

> It's been longstanding tzdb practice to model permanent DST as standard time. Admittedly this practice has so far been employed only for locations like Argentina that have fewer users. Still, the precedent is there and is consistent with the traditional meaning of standard time.
> There's another issue here: permanent DST is more likely to break software applications. For example, permanent DST in California that is called "PDT" and is 7 hours behind Greenwich would entail a POSIX-style TZ string like TZ='XXX6PDT7,0/0,J365/23' that means "California's standard time is 6 hours behind Greenwich, but it springs backward to 7 hours behind Greenwich on January 1 at 00:00 and springs forward on December 31 at 23:00, so it's actually on daylight saving time all year". I suspect these oddball TZ strings would break applications, and I doubt whether this approach would be wise even if it barely conforms to the standards.

Ah, I did not know this! Thank you Paul.

That does push things very strongly towards the ‘normalize everything as Standard Time’ approach.


| Frederick F. Gleason, Jr. |             Chief Developer             |
|                           |             Paravel Systems             |
|         A room without books is like a body without a soul.         |
|                                                                     |
|                                                         -- Cicero   |

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