[keithwinstein]

> Even more pedantically, “standard time” is not necessarily consistent across each zone (particularly, during the period for which in parts of the zone it is advanced by an hour) since "standard time” only advances for those states, or parts of states, for which an exemption is not in place.

I can't find a source (including 15 U.S.C. § 260a) that supports this reading, although I agree it's a little ambiguous. The law suggests that a region that doesn't observe DST is observing "the standard time otherwise applicable during that period" and is exempt from the provisions regarding advancement, not that "Pacific standard time" depends on where you are (see 15 U.S.C. § 263).

> So, the Unix-y convention [] is the simplest way

No argument there!

[dragonwriter]

> I can't find a source (including 15 U.S.C. § 260a) that supports this reading

From 15 USD § 260a, right after laying out the baseline rule for advancing standard time: “... however, (1) any State that lies entirely within one time zone may by law exempt itself from the provisions of this subsection providing for the advancement of time, but only if that law provides that the entire State (including all political subdivisions thereof) shall observe the standard time otherwise applicable during that period, and (2) any State with parts thereof in more than one time zone may by law exempt either the entire State as provided in (1) or may exempt the entire area of the State lying within any time zone.”

There are places that are exempt from the legal rule advancing standard time, hence, in those places, standard time does not advance.