At 02:36 PM 11/9/2015, Random832 wrote:
As far as I know, tzdb's policy is to have the "borders" of each zone exclusively follow de facto observance, without any distinction between "officially A, unofficially B" vs the bulk of the "B" zone, unless the situation changed some time between 1970 and now.
Interesting. For areas that have such unofficial deviations, there can be great discrepancy in the scope of observance, geographically and otherwise. For example, it US Federal facilities rarely observe an unofficial time zone. But there are exceptions - such as the Guadalupe Mountains National Park. Even local government may set their clocks to official time - but not always. City hall offices in Phenix City AL are set to Eastern Time. And where the lines get fuzzy, where the economic or social influence that led to the exception wanes, two next door neighbors may have their clocks set differently depending on where the most of the bread in that household is won or spent. When researching Fort Pierre SD I had one knowledgeable local resource tell me the observance extended about 50 miles west of the city. Another equally knowledgeable local insisted it was no more than 20 miles. So I guess that raises the question, what really *is* de facto observance. Regardless, I believe all of the exceptions I listed, and Hyder, predate 1970. Regards, Steve Jones Emacs!
