I would like to nominate this for a new item in the FAQ for R.
The FAQ should mention both the daylight-savings-time switch
and have a reference to the R-News article

Rich

On Tue, Oct 25, 2011 at 3:16 PM, Adrienne Wootten <amwootte@ncsu.edu> wrote:

> Ben,
>
> Thanks! That really helped.  Turns out all the data being used was in
> EST and currently the system timezone is EDT.  Thanks for the tip!
>
> A
>
> On Tue, Oct 25, 2011 at 2:27 PM, Ben Bolker <bbolker@gmail.com> wrote:
> > Adrienne Wootten <amwootte <at> ncsu.edu> writes:
> >
> >>
> >> R-listers,
> >>
> >> I have noticed several posts on issues with difftime producing NA's
> >> but they have been for older versions of R.  Here's the issue
> >> associated with difftime that I am dealing with in R 2.12.2.
> >>
> >>
> >> > difftime(strptime("03/11/2007 02:00",format="%m/%d/%Y
> > %H:%M"),preciptime,units="hours")
> >> Time difference of NA hours
> >>
> >
> >  I haven't checked, but I strongly suspect that this time
> > falls during the "leap forward" daylight-savings-time switch
> > in your current time zone, so that time doesn't actually exist
> > in your time zone ...
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
>
>
> --
> Adrienne Wootten
> Graduate Research Assistant
> State Climate Office of North Carolina
> Department of Marine, Earth and Atmospheric Sciences
> North Carolina State University
>
>  ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>

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