I noticed that android makes available a timezone for "US/Michigan". However, I can't find out what that actually is. It looks like most of Michigan is in Eastern and observes DST, and a small part of the UP is in Central and also observes DST. So why did android give them their own timezone, and why can't I find anything on the internet referencing Michigan having it's own time zone? Is this some sort of historical thing for the small number of years in the 70's that Michigan didn't observe DST?
This isn't related to Android specifically, but rather to the identifiers used by the IANA TZ Database, which you can read about in the timezone tag wiki, or on Wikipedia. Android is just one consumer of this data.
You can review the details of the time zones here, and you'll find that "US/Michigan" is an alias for "America/Detroit". This covers the parts of Michigan that are in the Eastern time zone.
You'll also find that Michigan has a second time zone, which is "America/Menominee", which covers the parts of Michigan that are in the Central time zone.
In general, you should use one of these two values rather than the "US/Michigan" alias. Also, if you don't care about historical time zone differences, then it would be acceptable to just use "America/Chicago" for Central time, and "America/New_York" for Eastern time.
The specific history of Michigan, including commentary, can be found in the source files of the TZ database itself. Specifically, it describes that Michigan didn't observe daylight saving time from 1968 to 1973, and that several counties switched from Eastern Time to Central Time in 1973. There are some other minor historical details as well.
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The client wants to see windows timezones, the ones at Time column here https://support.microsoft.com/en-us/help/973627/microsoft-time-zone-index-values except with UTC instead of GMT.
And also wants to see abbreviations. But I can't find any official windows timezones abbreviation list. What I find is IANA abbreviations.
We are goin to convert windows timezones to IANA timezones to work with time.
But the question is does IANA abbreviations=Windows timezones abbreviations?
If not where can I find the list of the rule for the windows abbreviations?
A few things:
The list you pointed at is not the official list of Microsoft Windows time zones. It is a copy of a very old static list from Windows Embedded 1.1., which has long been deprecated. There presently is no actively maintained list of all Windows time zones on a Microsoft web page.
To get a list of Windows time zones, call TZUTIL /L on the command line. It will return the ID and display name of each time zone installed on the system.
If you look at the CLDR zone mapping file, you'll see that many Windows zones map to more than one IANA zone. If you simply map the Windows zone to the 001 "golden zone", you may end up picking an IANA abbreviation that doesn't apply for the user. Thus, if you take the approach you described (converting to IANA and taking the IANA abbreviation), be sure to take the country code into consideration as well when doing the mapping.
Also:
There is no official single list of time zone abbreviations anywhere, because time zone abbreviations are not standardized. Many of the abbreviations we might use in English don't necessarily apply to non-English speakers, and many time zones don't have abbreviations at all.
Even in English, many time zone abbreviations are contradictory or ambiguous.
Some examples of problematic time zone abbreviations:
Does CST mean Central Standard Time, Cuba Standard Time, or China Standard Time?
Does IST mean India Standard Time, Israel Standard Time, or Ireland Standard Time?
Should Hawaii use HST or HAST?
Should HNE (Heure Normale de l'Est) be used instead of EST (Eastern Standard Time) in Quebec, Canada since its official language is French?
What is the time zone abbreviation of Minsk, Belarus? You might think MSK, but that's offensive to some because that abbreviation is also commonly used for Moscow, Russia. Belarus has one time zone for the whole country, and they don't speak English there. IANA gives the abbreviation as simply the numeric UTC offset +03 (since mid 2011).
Because of the above problems...
There is no official list of time zone abbreviations for Windows time zones. Windows doesn't use them.
You might find some time zone abbreviations listed in CLDR data, and exposed with various libraries and APIs, but they only sparsely populated in the data set. CLDR has not been reliably collecting or maintaining time zone abbreviations.
I have not been able to find an answer in the docs, and since the lowest level of aggregation is daily I cannot figure it out from the data. If I use the Google trends API (or trends.google.com), what is the time zone for the underlying data used in the aggregation? Is it UTC, my local time zone, the time zone of the country where the search was conducted?
The data is aggregated as full UTC days.
It used to be mentioned in the help center for Trends.
cet in the netherlands. Sirach for breakfast in your language
I use "Moment.js" and it's addition "moment-timezone" in a Web application that supports several languages (english, german, french etc.).
So to improve the user experience I'd like to know if there already exists a localization file (like the one for Moment.js) that can change timezone names from english to the desired language or do I need to write it myself?
For instance: String "Europe/Vienna" would be in that case changed to "Europe/Wien"
A few things:
What you're looking for doesn't exist in moment or moment-time zone.
You shouldn't actually change to "Europe/Wien". The time zone strings are IANA time zone identifiers, and are always in English.
In general, IANA time zone identifiers aren't designed for human readability. Translation to human readable names like "Central European Time" in English, or "Mitteleuropäische Zeit" in German, is the responsibility of the CLDR project.
You can use the Globalize library to get access to CLDR data in JavaScript, however AFAIK they don't currently have support for time zone names. I've requested this here.
Even with an adequate translation of IANA time zone ID to localized time zone names, it can be difficult to use this data to build time zone picker controls. I've done this in .NET with my TimeZoneNames library (demo here), but not in pure JS. I've yet to see a simple solution to this in JavaScript yet. If I ever find one (or create one), I'll come back here and update this answer.
Other alternatives you might consider are to use a map-based time zone picker, such as this one, or this one, and others.
import moment from 'moment';
import 'moment/locale/fr';
moment.locale('fr')
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I'm hoping somebody can resolve my issue with daylight savings and the country Jordan. According to joda-time 2.2 and 2.3 (at least), Jordan does in fact have daylight savings. My issue however is that there are many websites out there that claim that Jordan has in fact, removed all their daylight savings! Can any body verify for me which of these is correct?
Jordan has daylight savings... Yay, or Nay??
Thanks!
The most accurate, well-maintained, well-researched web site I know of for this is timeanddate.com. They have a specific page regarding Jordan's issues for this year, which says the following:
The Jordanian government recently announced that the country will continue observing daylight saving time (DST) all year for the second year in a row. The local time in Jordan and its capital Amman is 3 hours ahead of Coordinated Universal Time (UTC).
It has additional details, which I suggest you read if this is relevant to you.
The confusion you are probably encountering is because they are on daylight saving time, but they have cancelled any transitions back to standard time, so some may just interpreting that as a new standard time for them.
Joda Time uses the IANA TZDB, which is also very well maintained. Much of the data on timeanddate.com comes from there anyway.
For Jordan, you should have a time zone id of Asia/Amman. The recent changes for Jordan are reflected in version 2013f. Joda Time 2.3 shipped with 2013d, so you'll need to manually update to the latest data version following the instructions here.
If you'd like to see the specific changes made to the TZDB for Jordan in 2013, you can find them in this commit in the unofficial sources.
I've searched and found a couple of online web services that do this, but I was wondering it there's a database in the public domain which gives a list of latitudes and longitudes for the standard time zone lines? I'd like to be able to calculate what time zone a coordinate is without using a web service. I figured that time zone boundaries are mostly static and were probably decided by some committee, so there should be a CSV or GPX or KML somewhere.
I'd like to be able to check what time zone a coordinate lies in, for example:
48.856667 2.350833 is GMT+1 or CET
This is a series of files -- timezone polygons (shapefile), which you can transform into boundaries. With work on your part.
http://efele.net/maps/tz/world/
You should note that simply knowing the TZ does not guarantee that you know anything about the current correct time or date there in terms of the local calendar. Time Ex: The Isreali Knesset (parliament) decides when Daylight time starts and ends - sometimes they have chosen a date in the past. Date Ex: The Hijri Calendar changes months based on the ability of people in Mecca to actually observe the new moon from there. Cloudy days alter the date.
Askgeo.com has a Java library under commercial license. (Scroll down their page to find information about it). They charge 2 grand up front for it though, considering the amount of work they must have put in compiling loads of vector maps, etc, I can understand they want the money.
I use their free API, but you wanted something downloadable, and I think this is one of your few bets.
I tried openstreetmap and they have the data, but it would be buried in a map of Earth, not completely useful itself. Here is one on Wikipedia though: http://en.wikipedia.org/wiki/List_of_tz_database_time_zones
I recently found this data here:
https://github.com/straup/whereonearth-timezone