How to look up historical time zones by date and location (was: How can I get the timezone time of a location?)

[Ben Finney]

luofeiyu <elearn2014 at gmail.com> writes:

> I knew there is a difference between localtime and timezone time.
> Localtime: The official time in a local region (adjusted for location
> around the Earth); established by law or custom.
> Timezone: Any of the 24 regions of the globe (loosely divided by
> longitude) throughout which the same standard time is used.

That is not what “time zone” means and you're going to continue being
confused if you apply that definition. See the consensus definition at
<URL:https://en.wikipedia.org/wiki/Time_zone>.

> For Urumqi,localtime is the time of east 8 timezone, but timezone time
> is the time of east 6 timezone.

How have you determined these? Who declares “east 6” for Urumqi
currently? Why should you expect a timezone database to contain that
timezone for current time in that location.

By the international time zone database, the time zone for Urumqi is
currently “China Standard Time”, UTC+8 hours. That time zone is true for
all dates since 1949 to the present day.

Are you perhaps asking not about *current* time zone, but time zones at
a different point in time? Historical time zones in China have differed
<URL:https://en.wikipedia.org/wiki/Historical_time_zones_of_China>.
Those historical time zones are in the standard time zone database, but
only apply to specific date ranges.

-- 
 \        “… no testimony can be admitted which is contrary to reason; |
  `\   reason is founded on the evidence of our senses.” —Percy Bysshe |
_o__)                        Shelley, _The Necessity of Atheism_, 1811 |
Ben Finney