Some countries are observing daylight saving, but I want to get the timezone name irrespective of daylight saving.
In short I want standard time of such countries instead of daylight saving time.
Is there any way to convert this or anything else?
P.S. I want this because of my server requirement.
//----------------------------------------------------------------
I have seen this reference in apple.
+ (instancetype)timeZoneForSecondsFromGMT:(NSInteger)seconds
Discussion The name of the new time zone is GMT +/– the offset, in
hours and minutes. Time zones created with this method never have
daylight savings, and the offset is constant no matter the date.
But I wonder how it will useful to me for my problem? As I want timezone name without daylight saving not any time with offset.
If you just need the time zone with respect to GMT without accounting for DST, the simplest option would be to:
Find the DST offset using 'daylightSavingTimeOffset' on your suspect time zone.
Subtract that value from the timezone's GMT offset.
Create a new time zone with the now adjusted offset.
If you need the name of the standard time zone, the simplest approach might just be to look for "DST" and "Daylight" in the time zone description and then pick the time zone that has the greatest number of words matching to the DST time zone. That might not be the most elegant solution, but it would work for most time zones.
It was actually this
typedef enum : NSInteger {
NSTimeZoneNameStyleStandard,
NSTimeZoneNameStyleShortStandard,
NSTimeZoneNameStyleDaylightSaving,
NSTimeZoneNameStyleShortDaylightSaving,
NSTimeZoneNameStyleGeneric,
NSTimeZoneNameStyleShortGeneric
} NSTimeZoneNameStyle;
The enum answered it for me. My bad , I should have read this earlier.
Related
I trying to parse a date in ISO 8601 format and some moments aren't clear for me.
For example, I have the next date: 2020-04-16T07:16:34.858215+03:00 in Europe/Moscow timezone.
Does it mean 07:16 in Moscow time or 10:16? I mean do I need to add 3 hours to date or date is in Moscow time already and timezone just shows how it diffs from UTC?
P.S. I tried to find information about it but everywhere is just common format description without details.
The time specified is the local time, so 2020-04-16T07:16:34.858215+03:00 means 7:16am in Moscow, or 4:16am UTC.
Wikipedia has a good example which clarifies things to at least some extent:
The following times all refer to the same moment: "18:30Z", "22:30+04", "1130−0700", and "15:00−03:30". Nautical time zone letters are not used with the exception of Z. To calculate UTC time one has to subtract the offset from the local time, e.g. for "15:00−03:30" do 15:00 − (−03:30) to get 18:30 UTC.
It's really unfortunate that ISO-8601 talks about this as a time zone, when it's only a UTC offset - it definitely doesn't specify the actual time zone. (So you can't tell what the local time will be one minute later, for example.)
how can we convert the GMT to local SQL DATE?
When i store GMT time , then 1 hour is subtracted from this value.
please help me.
Your question is a bit ambiguous as written, but I am guessing that you want to convert a UTC datetime (sometimes called GMT or Zulu time) into a datetime in your local timezone.
You indicate that your local time zone is -1 hour offset from UTC time.
In this case you simply use the DATEADD function:
SET MyTimeLocal = DATEADD(HH, -1, MyTimeGMT)
Note that this will only work so long as your time zone really is one hour before UTC time. If your location uses daylight saving time, this will be wrong as soon as the time changes, and it will be extra wrong when the time to be converted falls in the crack of the clock change.
There are many better ways to do this in general, but to give a general solution we would need to know what version of SQL is being used and what exactly you are trying to accomplish.
I am creating a Rails API that will be consumed by a Javascript framework. Time display and manipulation will be controlled with MomentJS. It is important for the front-end to be able to display the dates along with the time zone abbreviations (e.g. 1/1/2010 11:00 PST).
From what I understand, an offset (e.g. -0700) is not enough to determine the actual timezone, and the timezone abbreviations aren't always unique.
I can think of only two options to solve this:
Return all times in UTC and have an extra field for each time specifying the timezone (e.g. { pick_up: "17-06-08T18:59:21.215Z", pick_up_tz: 'America/New_York' } (or pick_up_tz: 'PST')
Use a non-standard datetime format, something that includes both the timezone abbreviation and the offset (e.g. { pick_up: "17/09/06 13:34:00 CDT -05:00")
Are these reasonable solutions or is there a better way?
Use a non-standard datetime format
Never do this. An API should always return time in ISO 8601.
Return all times in UTC and have an extra field for each time specifying the timezone
You are correct that an offset is insufficient to identify time zone, so you do need to include that in the API response, ideally as an IANA time zone.
Whether you convert to UTC or include an offset is a matter of preference; 2017-06-08T18:59:21.215Z and 2017-06-08T11:59:21.215-0700 mean the same time, regardless of the time zone you convert to for display. Including the offset can be useful to identify if the stored offset is different from the time zone, as you might only show the time zone qualifier if the offset is different.
In XQuery, how can I determine whether a UTC time falls within daylight saving time in a region?
Something like:
declare function local:IsDaylightSavingTime($utcDateTime as xs:utcDateTime, timeZone xs:dayTimeDuration) as xs:boolean {
...
}
This is not possible.
How would you expect a time zone to be represented by an xs:dayTimeDuration? That would assume a time zone is the same thing as a time zone offset, which it is not. Please read the timezone tag wiki.
Besides, any program that is capable of performing this function needs some type of time zone database. While it is conceivable that a particular XQuery implementation decided to incorporate a time zone database, that certainly wouldn't be in the XQuery language itself.
Not sure if the title of my question was accurate so sorry if it's misleading, here goes.
I am doing some work with that involves timezones and i just want to make sure i get this right... if i want something to start at 03:00:00 my time and my timezone offset is -5 all i need to do is add 5 to 03:00:00 giving me 08:00:00 and that is the UTC time?
It depends what you mean by "timezone offset". Usually an offset is expressed as the amount added to UTC to get to local time, in which case you need to subtract it from the local time in order to get back to UTC (so it would be 22:00 on the previous day in your case).
So for example, Pacific Daylight Time has an offset of -7 - it's 7 hours behind UTC.
However, there are situations (annoyingly) where the offset is expressed the other way round, so make sure you know which way is appropriate for your specific context.
Note that knowing the offset doesn't mean you know the time zone - there can be multiple time zones with the same offset for a particular moment, but different rules for when the offset changes.
...Yes. Depending on what language you're doing it in, it may or may not be as easy as writing
time-offset;