Interpretation of the question means “are there any cities that are in more than one time zone”, then the answer is “yes”. And there are American states with several time zones (Indiana and Arizona are two of them).
A recent discussion on the TZ mailing list is about the area of China known as Xinjiang, which has a mixed population of Han and Uighurs. It appears that Khan uses the standard Chinese time zone (Asia / Beijing), but Uyghurs often use the local time zone. It is now encapsulated in an Olson database named Asia / Urumqi for Uyghur time zone.
So, for example, the zone.tab file in tzdata2010b.tar.gz, available from ftp://elsie.nci.nih.gov/pub/tzdata2010b.tar.gz (code ftp://elsie.nci.nih.gov/ pub / tzcode2009t.tar.gz ). There is a detailed description of how and why the changes were made to the asia file.
Please note that the Olson (Time Zone) database is now available (2016-09-19), available from IANA at https://www.iana.org/time-zones , and not from NIH. You can get the current release quite easily; getting historical releases can be tricky.
Yes, time zones do change 20 times a year around the world, and sometimes they hardly notice (i.e. the government accepts amendments to changes only a day or two before the change).
@basit asks:
Wow about 20 times a year around the world. I am trying to register the time zone for latitude and longitude, so now my question will be, how long should I register the data? 6 months? 1 month? 2 .. 3 ..?
And also, how much time is required for daylight saving time to change during the year, because I need to register the time zone with summer day and update the data after a certain period.
I mean, during 2009, there were 20 problems in the time zone database, due to changes in the rules, at least in many places. However, any country usually changes its rules only once - although in Argentina, different states changed their rules at different times and exacerbated problems.
I don’t understand that we have enough information to tell you how long to record the data. I would be inclined to speak for at least 12 months, but it depends on what you are going to do with it. At one level, all you have to do is keep up with the Olson database, which will tell you timezone rules essentially all over the world. If you are interested in tracking the time zones of your visitors, you can store data as much as you want. Since not everyone uses the canonical Continent / City notation for their time zone (for example, I use the older US / Pacific notation, which is still supported but equivalent to America / Los_Angeles). Classical notations such as TZ = EST5EDT are ambiguous; both the USA and Australia have time intervals that use EST as an abbreviation, as well as dates when the transition between standard time and daylight saving time occurs (see the bulk of the data in the Olson database).
You also ask how long it takes to change the time zone. I'm not sure what you mean. As for "when the clock changes (between standard and summer time)", it is "instantly"; one second - one time zone offset; the next second is different. If you mean “how long does it take for governments to change their minds,” this is changing radically. For example, both Europe and the United States have relatively fixed rules that change every few years; the rule in the USA was stable for about 20 years, then they changed the rules about 3 years ago. Europe is alike. On the other hand, some countries change their rules annually. I got the impression that some Islamic countries set up when they switch between standard time and summer time (or vice versa), depending on when Ramadan falls - if this happens during Ramadan, then they bring it forward or delay it, so the rule does not change during Ramadan. Other countries have different reasons for continuing the battle, perhaps the political equivalent of a release deadline. Thus, it can take quite a while for people to decide what the “final” (which means “next edition”) rules for a given year mean.
The website http://worldtimezone.com/ does a pretty good job of tracking most of these idiosyncrasies.