I know this looks simple.
In a Google spreadsheet, I have a column where I enter time in one timezone (GMT) And another column should automatically get time in another time zone(Pacific Time)
GMT | PT
----------|------------
5:00 AM | 9:00 PM
As of now I am using
=$C$3-time(8,0,0)
The problem here is, I want to change the time formula for Daylight savings.
Is there any function or script available which can take the daylight saving into calculation automatically.
Short answer
There is no built-in function but you could build a custom function.
Example
/**
* Converts a datetime string to a datetime string in a targe timezone.
*
*@param {"October 29, 2016 1:00 PM CDT"} datetimeString Date, time and timezone.
*@param {"GMT"} timeZone Target timezone
*@param {"YYYY-MM-dd hh:mm a z"} Datetime format
*@customfunction
*/
function myFunction(datetimeString,timeZone,format) {
var moment = new Date(datetimeString);
return Utilities.formatDate(moment, timeZone, format)
}
Explanation
In order to consider daylight saving time zones the input argument for of the value to be converted should include the date, no only the time of the day. You could set a default date and time zone to build the datetimeString by concatenating it before calling the formula.
=myFunction("October 29, 2016 "&A2&" GMT","PDT","hh:mm a")
Update
Besides using three letter timezone codes, we can also use TZ database names like America/Los_Angeles, example:
=myFunction("October 29, 2016 "&A2&" GMT","America/Los_Angeles","HH:mm")
See also
References
This tutorial was amazingly helpful: https://davidkeen.com/blog/2017/01/time-zone-conversion-in-google-sheets/
Google Sheets does not have a built in way of converting time zone data but by using the power of Moment.js and Google’s script editor we can add time zone functionality to any sheet.
These are the files I copied into my script project:
- https://momentjs.com/downloads/moment-with-locales.js saved as moment.js
- https://momentjs.com/downloads/moment-timezone-with-data.js saved as moment-timezone.js
Make sure you add the moment.js script first and have it above the moment-timezone.js script because moment-timezone.js depends on it.
Then in your other script project, your Code.gs file can look like this:
var DT_FORMAT = 'YYYY-MM-DD HH:mm:ss';
/**
https://stackoverflow.com/questions/34946815/timezone-conversion-in-a-google-spreadsheet/40324587
*/
function toUtc(dateTime, timeZone) {
var from = m.moment.tz(dateTime, DT_FORMAT, timeZone);//https://momentjs.com/timezone/docs/#/using-timezones/parsing-in-zone/
return from.utc().format(DT_FORMAT);
}
/**
https://stackoverflow.com/questions/34946815/timezone-conversion-in-a-google-spreadsheet/40324587
*/
function fromUtc(dateTime, timeZone) {
var from = m.moment.utc(dateTime, DT_FORMAT);//https://momentjs.com/timezone/docs/#/using-timezones/parsing-in-zone/
return from.tz(timeZone).format(DT_FORMAT);
}
That can also be done without macros. Just using functions and data manipulation will suffice. Explaning the whole process here would be a bit cumbersome. Just do your research on how the various time functions work and use your creativity.
Hint: Use =NOW() if you want both current date and time. You'll actually need that if you need to find out the precise diff in time between to different dates.
Use =NOW()-INT(NOW()) when you only want the time (with date truncated if both times fall on the same date). Then format the corresponding cell or cells for time (i.e. 4:30 PM), not for date-time (3/25/2019 17:00:00). The latter is the format you'd use when you want to show both date and time... like when you use NOW().
Also search online for the Daylight Saving Time offset for the various standard time zones (PT, MT, CT, ET, AT) with respect to the Coordinated Universal Time (UTC). For example, in 2019 the offset for Pacific Time is UTC-7 when DST is observed starting on March 10 at 2 AM (Pacific) until November 3 at 2 AM. That means that the difference in time from UTC to Pacific is 7 hours. During the rest of the year is 8 hours (UTC-8). During DST observance starting sometime in March (the 10th this yr) it goes from PST to PDT by moving clocks forward 1 hr, or what we know as UTC-7 (that's summer time). After DST observance it goes from PDT to PST by moving clocks back 1 hr again, or what we know as UTC-8 (or winter time). Remember that the clock is advanced one hour in March to make better use of time. That's what we call DST, or Daylight Saving Time. So after March 8 at 2 AM (this year in 2019) we are in UTC-7. In November, we do the opposite. In Nov 3 at 2 AM the clock is taken back one hour as the winter kicks in. At that point we are back in Standard Time. Seems a bit confusing but it's really not.
So, basically, for folks in PT they go from PST to PDT in March and from PDT to PST in November. The exact same process goes on with Mountain Time, Central Time and Eastern Time. But they have different UTC time offsets. MT is either UTC-6 or UTC-7. CT is either UTC-5 or UTC-6. And ET is either UTC-4 or UTC-5. All depending on whether we are in summer time when Daylight Saving is observed to make better use of daylight and working hours, or in winter time (AKA, Standard Time).
Study these thoroughly and understand how they work, and play around with the various time functions in Excel or Google Sheets like the TIME(#,#,#) and NOW() functions and such, and believe me, soon you'll be able to do about anything like a pro with plain functions without having to use VBA Google Apps Script. You can also use the TEXT() function, though, with tricks like =TEXT(L4,"DDD, MMM D")&" | "&TEXT(L4,"h:mm AM/PM"), where L4 contains you date-timestamp, to display time and date formats. The VALUE() function also comes in handy every now and then. You can even design a numerical countdown timer without the use of macros. You'd need to create a circular reference and set iterations to 1, and time display to say every 1 min, in your spreadsheet settings for that.
The official timeanddate dot com website is a good source of info for all to know about time zones and how daylight time is handled. They have all UTC offsets there too.
来源：https://stackoverflow.com/questions/34946815/timezone-conversion-in-a-google-spreadsheet