title: Dealing with Eastern Standard Time (EST) and Eastern Daylight Savings (EDT) in R
body: <p>I have a series of datasets from a water quality continuous monitoring probe with the Date and Time set in Eastern Standard Time (EST) so there is no correction of Daylight Savings Time (EDT). In R, the fields are recognized as factors when importing the data table from an MS access database however when converting using as.POSIXct() dates and times from 02:00 (24 clock) on 2016-03-13 become NAs. This is due to the transition from EST to EDT...therefore technically 2016-03-13 02:00 doesn't exist. </p>
  
  <p>Some created data as an example</p>
  
  <p><code>test&lt;-data.frame(Date=rep(as.Date("2016-03-13"),120),Hour=rep(seq(0,23,1),5),Min=rep(seq(0,60,15),24))</code></p>
  
  <p>Is there a way to convert the factor or character field to as POSIXct field while retaining the EST timezone designation? Alternatively is there a way to identify and convert the proper date and times into EST and EDT? </p>
  
  <p>I have gone around and around and can't get anything to work. I have attempted to convert to GMT (or UTC) then convert back to EST (tz="America/New_York"). I realize that this is an ongoing issue and people who work with date and time data, especially in R would love to move away from EDT.  </p>
  
  <p>Any help is appreciated...I am at my wits end on this one.</p>