Contributor
Posts: 20

# Is there a way to convert time from EST to GMT?

Can SAS convert time from EST to GMT accounting for daylight saving? Or do I have to incorporate daylight saving days manually?

Super Contributor
Posts: 543

## Re: Is there a way to convert time from EST to GMT?

http://listserv.uga.edu/cgi-bin/wa?A2=ind0711a&L=sas-l&P=8219

data _null_;

gmt = '20:05:09't;

est = gmt - (4*60*60);

pst = gmt - (7*60*60);

format _all_ time.;

put _all_;

run;

and here is another discussion:

Contributor
Posts: 20

## Re: Is there a way to convert time from EST to GMT?

Thanks. I saw this link earlier too. But it seems to work for daylight saving time only, in other cases we need to have est = gmt - (5*60*60) . I was wondering whether SAS can automatically identify days with DST.

Super Contributor
Posts: 543

## Re: Is there a way to convert time from EST to GMT?

from quickly scanning the internet, it seems that there is no automatic way to calculate it.

Posts: 3,867

## Re: Is there a way to convert time from EST to GMT?

This seems close but you will need "date time".

data _null_;

do local='03feb2012:01:03:03'dt, '04jul2012:01:03:03'dt, datetime();
s = dhms(nwkdom(2,1, 3,year(datepart(local))),2,0,0);
e = dhms(nwkdom(1,1,11,year(datepart(local))),2,0,0);
adj = s le local le e;
offset =
gmt = local + dhms(0,offset,0,0);
put (_all_) (=);
end;

format gmt local s e datetime20.;

run;
I forgot to mention this
Also if you are collecting time approaching 2am on "fall back day" what do you write down at 2am, the clock has been reset to 1am.   Instead of collecting in local time and converting to GMT you need to do it the other way round. Don't you?
Posts: 1,318

## Re: Is there a way to convert time from EST to GMT?

DN gave a great response...  Daylight savings time is not some difficult unknown.  It occurs on the between then 2nd Sunday of March and the 1st Sunday of November, at 2:00am...

Another way to check could be to use the TimeZone class

proc groovy classpath=cp;

submit parseonly;

class DST {

static boolean isDst(String tmz) {

return TimeZone.getTimeZone(tmz).inDaylightTime(new Date())

}

}

endsubmit;

run;

data test;

declare javaobj j('DST');

j.callStaticBooleanMethod('isDst',"EST",is_dst);

put is_dst=;

run;

is_dst=0;

est = gmt - ((5-(1*is_dst))*60*60);

Super User
Posts: 8,220

## Re: Is there a way to convert time from EST to GMT?

Here is a file that contains timezone by zipcode, including whether dst is used in each zipcode.  And, since its timezones are already shown as difference from GMT, you only need to code whether to add the hour or not based on the date.  PS: its free!:

Free Zip Code Latitude and Longitude Database

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