[tz] Anecdotal discrepancy for Navajo nation in Arizona

[Brian Inglis]

On 2016-05-24 16:55, Arthur David Olson wrote:
> On Tue, May 24, 2016 at 6:43 PM, Deborah Goldsmith
> <goldsmit at apple.com <mailto:goldsmit at apple.com>> wrote:
>> A colleague recently visited Page, Arizona, and the Navajo
>> reservation right next to it.
>> His phone must have been associated with a cell tower inside the
>> Navajo nation, because his zone was set by NITZ to America/Denver
>> (DST in effect). This matches the current TZ database. However, he
>> observed that the parts of the Navajo nation adjacent to Page were
>> actually observing the same time zone as Page (America/Phoenix, DST
>> not in effect).
>> I wouldn’t make any changes based on this one anecdote, but it might
>> be worth checking if anyone has any sources inside the Navajo
>> nation.
> The source used back in 1987 (using--ahem--snail mail) was the Inter
> Tribal Council of Arizona: http://itcaonline.com/.

Nothing has changed in AZ, which has a daylight saving donut:
http://www.lapahie.com/Pictures/Navajo_Map_Lg.jpg
http://www.azcentral.com/story/news/local/arizona/2016/03/12/arizona-daylight-saving-time-navajo-hopi-nation-reservation/81597184/
http://www.cntraveler.com/stories/2012-11-12/daylight-saving-donut-arizona-ken-jennings-maphead

TL;DR:
The Navajo nation includes areas in UT, CO, NM, which observe DST,
so the parts in AZ also observe DST.
Federal facilities and areas within AZ are subject to federal
legislation so they too observe DST.
The Hopi nation, encircled by the Navajo nation, but wholly within
AZ, stays on MST.
Page, while within the boundaries of the Navajo nation, was swapped
for state land, so stays on MST.

The time observed in any location will depend on the applicable
legislation, and/or its main commercial links.
The time you get from any cell tower may depend on its location
and/or what the company considers its main service area.

How do OS X and iOS deal with local time in AZ/Navajo/Hopi/Page,
and federal parks and facilities  in AZ?

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada