From https://www.timeanddate.com/time/zones/sst, the time zone is UTC -11. However, when I get timezone info from .NET. It is the UTC +13.
var timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("Samoa Standard Time");
timeZoneInfo is UTC +13.
How can I get the correct time zone info of Samoa Standard Time (SST) in .Net
Samoa (officially The Independent State of Samoa) and American Samoa are in two different time zones, on opposite sides of the international date line.
Image source: Wikimedia Commons
The Independent State of Samoa observes UTC+13 during standard time and UTC+14 during daylight saving time.
Its Windows time zone identifier is "Samoa Standard Time"
Its IANA time zone identifier is "Pacific/Apia"
American Samoa observes UTC-11 the whole year.
Its Windows time zone identifier is "UTC-11"
Its IANA time zone identifier is "Pacific/Pago_Pago"
As always:
Use Windows identifiers with .NET Framework and .NET Core when running on Windows.
Use IANA identifiers with .NET Core when running on Linux.
Use the TimeZoneConverter library to use either form of identifier on either platform.
Related
I am using below code to get time zone details for "Gulf Standard Time", but its throwing error as below
The time zone ID 'Gulf Standard Time' was not found on the local computer.
below is line of code i am using
TimeZoneInfo tZone = TimeZoneInfo.FindSystemTimeZoneById("Gulf Standard Time");
Can you please tell me what exactly is the issue in code, as i have checked and its correct time zone name.
As pointed out in comments, "Gulf Standard Time" isn't a valid Windows time zone identifier.
Gulf Standard Time usually refers to UTC+04:00 with no DST, as observed in the United Arab Emirates and Oman, as described here. The corresponding time zone in Windows appears with an English display name of (UTC+04:00) Abu Dhabi, Muscat, and has a corresponding ID of Arabian Standard Time.
Thus in .NET:
TimeZoneInfo tZone = TimeZoneInfo.FindSystemTimeZoneById("Arabian Standard Time");
Console.WriteLine(tzone.DisplayName);
// prints: (UTC+04:00) Abu Dhabi, Muscat
To get a list of supported time zones, use TimeZoneInfo.GetSystemTimeZones() in your .NET code, and examine the Id and DisplayName properties. Alternatively, you can call TZUTIL /L on the command line to list them.
Also, just to point out that this all assumes you are running on Windows. If you are actually running .NET Core on non-Windows systems (Linux, OSX, etc.), then you should uses IANA time zone IDs. In this case, either "Asia/Dubai", or "Asia/Muscat" would be appropriate.
And if your code might run both on Windows and Non-Windows systems, then you will need to take advantage of my TimeZoneConverter library.
As described in the timezone tag wiki, there are two different styles of time zones.
Those provided by Microsoft for use with Windows and the .Net TimeZoneInfo class (when running on Windows) are identified by a value such as "Eastern Standard Time".
Those provided by IANA in the TZDB, and used by the .NET TimeZoneInfo class when running on Linux or OSX, are identified by a value such as "America/New_York".
Many Internet-based APIs use the IANA time zones, but for numerous reasons one might need to convert this to a Windows time zone id, or vice-versa.
How can this be accomplished in .Net?
Current Status:
Starting with .NET 6, both forms of time zones are supported on any platform that has both time zone data and ICU installed, which is most installations of Windows, Linux, and MacOS. See Tobias's answer.
Original Answer:
The primary source of the data for conversion between Windows and IANA time zone identifiers is the windowsZones.xml file, distributed as part of the Unicode CLDR project. The latest dev version can be found here.
However, CLDR is released only twice annually. This, along with the periodic cadence of Windows updates, and the irregular updates of the IANA time zone database, makes it complicated to just use the CLDR data directly. Keep in mind that time zone changes themselves are made at the whim of the world's various governments, and not all changes are made with sufficient notice to make it into these release cycles before their respective effective dates.
There are a few other edge cases that need to be handled that are not covered strictly by the CLDR, and new ones pop up from time to time. Therefore, I've encapsulated the complexity of the solution into the TimeZoneConverter micro-library, which can be installed from Nuget.
Using this library is simple. Here are some examples of conversion:
string tz = TZConvert.IanaToWindows("America/New_York");
// Result: "Eastern Standard Time"
string tz = TZConvert.WindowsToIana("Eastern Standard Time");
// result: "America/New_York"
string tz = TZConvert.WindowsToIana("Eastern Standard Time", "CA");
// result: "America/Toronto"
There are more examples on the project site.
It's important to recognize that while an IANA time zone can be mapped to a single Windows time zone, the reverse is not true. A single Windows time zone might be mapped to more than one IANA time zone. This can be seen in the above examples, where Eastern Standard Time is mapped to both America/New_York, and to America/Toronto. TimeZoneConverter will deliver the one that CLDR marks with "001", known as the "golden zone", unless you specifically provide a country code and there's a match for a different zone in that country.
Note: This answer has evolved over the years, so comments below may or may not apply to the current revision. Review the edit history for details. Thanks.
Starting with .NET 6, it is finally possible to work with time zones in a cross-platform manner, so these manual workarounds are no longer needed.
The TimeZoneInfo.FindSystemTimeZoneById(string) method automatically accepts either Windows or IANA time zones on either platform and converts them if needed.
// Both of these will now work on any supported OS where ICU and time zone data are available.
TimeZoneInfo tzi1 = TimeZoneInfo.FindSystemTimeZoneById("AUS Eastern Standard Time");
TimeZoneInfo tzi2 = TimeZoneInfo.FindSystemTimeZoneById("Australia/Sydney");
Note that, as specified on the link, the .NET Core Alpine Linux-based Docker images do not have the necessary tzdata installed by default, so it must be installed in your Dockerfile for this to work correctly.
I know this is an old question, but I had a use case I though I would share here, since this is the most relevant post I found when searching. I was developing a .NET Core app using a docker linux container, but for deployment on a windows server. So I only needed my docker linux container to support the windows timezone names. I got this working without changing my application code by doing the following:
cp /usr/share/zoneinfo/America/Chicago "/usr/share/zoneinfo/Central Standard Time"
cp /usr/share/zoneinfo/America/New_York "/usr/share/zoneinfo/Eastern Standard Time"
cp /usr/share/zoneinfo/America/Denver "/usr/share/zoneinfo/Mountain Standard Time"
cp /usr/share/zoneinfo/America/Los_Angeles "/usr/share/zoneinfo/Pacific Standard Time"
Then, in my .NET code, the following worked without any modification: TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time")
As described in the timezone tag wiki, there are two different styles of time zones.
Those provided by Microsoft for use with Windows and the .Net TimeZoneInfo class (when running on Windows) are identified by a value such as "Eastern Standard Time".
Those provided by IANA in the TZDB, and used by the .NET TimeZoneInfo class when running on Linux or OSX, are identified by a value such as "America/New_York".
Many Internet-based APIs use the IANA time zones, but for numerous reasons one might need to convert this to a Windows time zone id, or vice-versa.
How can this be accomplished in .Net?
Current Status:
Starting with .NET 6, both forms of time zones are supported on any platform that has both time zone data and ICU installed, which is most installations of Windows, Linux, and MacOS. See Tobias's answer.
Original Answer:
The primary source of the data for conversion between Windows and IANA time zone identifiers is the windowsZones.xml file, distributed as part of the Unicode CLDR project. The latest dev version can be found here.
However, CLDR is released only twice annually. This, along with the periodic cadence of Windows updates, and the irregular updates of the IANA time zone database, makes it complicated to just use the CLDR data directly. Keep in mind that time zone changes themselves are made at the whim of the world's various governments, and not all changes are made with sufficient notice to make it into these release cycles before their respective effective dates.
There are a few other edge cases that need to be handled that are not covered strictly by the CLDR, and new ones pop up from time to time. Therefore, I've encapsulated the complexity of the solution into the TimeZoneConverter micro-library, which can be installed from Nuget.
Using this library is simple. Here are some examples of conversion:
string tz = TZConvert.IanaToWindows("America/New_York");
// Result: "Eastern Standard Time"
string tz = TZConvert.WindowsToIana("Eastern Standard Time");
// result: "America/New_York"
string tz = TZConvert.WindowsToIana("Eastern Standard Time", "CA");
// result: "America/Toronto"
There are more examples on the project site.
It's important to recognize that while an IANA time zone can be mapped to a single Windows time zone, the reverse is not true. A single Windows time zone might be mapped to more than one IANA time zone. This can be seen in the above examples, where Eastern Standard Time is mapped to both America/New_York, and to America/Toronto. TimeZoneConverter will deliver the one that CLDR marks with "001", known as the "golden zone", unless you specifically provide a country code and there's a match for a different zone in that country.
Note: This answer has evolved over the years, so comments below may or may not apply to the current revision. Review the edit history for details. Thanks.
Starting with .NET 6, it is finally possible to work with time zones in a cross-platform manner, so these manual workarounds are no longer needed.
The TimeZoneInfo.FindSystemTimeZoneById(string) method automatically accepts either Windows or IANA time zones on either platform and converts them if needed.
// Both of these will now work on any supported OS where ICU and time zone data are available.
TimeZoneInfo tzi1 = TimeZoneInfo.FindSystemTimeZoneById("AUS Eastern Standard Time");
TimeZoneInfo tzi2 = TimeZoneInfo.FindSystemTimeZoneById("Australia/Sydney");
Note that, as specified on the link, the .NET Core Alpine Linux-based Docker images do not have the necessary tzdata installed by default, so it must be installed in your Dockerfile for this to work correctly.
I know this is an old question, but I had a use case I though I would share here, since this is the most relevant post I found when searching. I was developing a .NET Core app using a docker linux container, but for deployment on a windows server. So I only needed my docker linux container to support the windows timezone names. I got this working without changing my application code by doing the following:
cp /usr/share/zoneinfo/America/Chicago "/usr/share/zoneinfo/Central Standard Time"
cp /usr/share/zoneinfo/America/New_York "/usr/share/zoneinfo/Eastern Standard Time"
cp /usr/share/zoneinfo/America/Denver "/usr/share/zoneinfo/Mountain Standard Time"
cp /usr/share/zoneinfo/America/Los_Angeles "/usr/share/zoneinfo/Pacific Standard Time"
Then, in my .NET code, the following worked without any modification: TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time")
I have a system which consists of a C# back end and a Java front end. The C# back end communicates with other systems and some mobile devices.
On the C# side, my task is among others to recognize the time zone of the timestamps coming from the mobile devices and create the corresponding TimeZoneInfo object. This is working without any problems.
On the Java side, I have to display the time zone information together with the data sent by a mobile device. I'm using the TimeZone class to store the time zone information within my domain objects.
Now the question is how can I create a Java's TimeZone object which corresponds with a C#'s TimeZoneInfo object? AFAIK the time zones do not have any unique IDs. Further on, the names are also different (e.g. in C#: "Central Europe Standard Time", in Java "Central Europe Time"). Not even the number of the time zones in C# and in Java is equal!
You know that "time" is independent of "time zone", so I won't belabor that point :)
"TimeZone" is really more a function of your OS than a programming language.
Android "Time Zone IDs" correspond to the standard, IANA "Olson database":
http://developer.android.com/reference/java/util/TimeZone.html#getTimeZone%28java.lang.String%29
http://en.wikipedia.org/wiki/Tz_database
The other half of the equation is mapping .Net timezones to the "standard". This link should help:
.NET TimeZoneInfo from Olson time zone
As paulsm4 says, you can map Windows names to TZDB (aka Olson, aka tz, aka zoneinfo) names - although the mapping changes periodically, and you should really look at Unicode CLDR for more details. You should be aware that the format of the mapping table has changed over time, and that some Windows IDs map to multiple TZDB IDs. (Some are missing entirely.)
As an alternative, you could consider abandoning Windows time zone IDs entirely, and use TZDB throughout the stack, if you use Noda Time, a .NET date/time API I've been working on for a while now. You'll also find your Java date/time work easier if you use Joda Time, which is the library I based the "engine" of Noda Time on. It's much nicer than using Date and Calendar in Java.
I have the following list of time zones that a user can choose from, Mountain Standard Time is in there twice for Arizona. These aren't want they see when they choose. I pulled this list of a website that had all of Microsofts time zones. I guess I'm confused if it had Mountain Standard Time listed for the regular states and AZ.
Hawaiian Standard Time
Alaskan Standard Time
Pacific Standard Time
Mountain Standard Time
Mountain Standard Time
Central Standard Time
Central America Standard Time
Eastern Standard Time
U.S. Eastern Standard Time
My question is I'm guessing these don't account for DST, so I'm assuming I need to add something to my conversion to check and see if they're in DST and adjust it accordingly. Here is how I'm doing the conversion now.
TimeZoneInfo time = TimeZoneInfo.FindSystemTimeZoneById(LocationProvider.GetLocation(LocationID).TimeZone.Name);
return TimeZoneInfo.ConvertTime(DateTime.Now, time);
Yes, TimeZoneInfo accounts for DST, so long as you use it properly (which isn't as easy as it might be, admittedly). It's not really clear why you're trying to do what you're doing though...
I know it's confusing that the ID is actually the standard ID for the time zone, but it's still a full time zone that knows about DST. It doesn't just mean "standard time".
(If you get frustrated with DateTime et al and fancy trying Noda Time for all your date/time needs, I'd be happy to help out :)