title: Use of as.POSIXct and understanding timezone in time series- R
body: <p>I am looking to set x-axis limits on a rather simple time series plot in R.
  My plot produces limits that are 6 hours <em>ahead</em> of my time zone (plot would start and end at 14:00:00 in the example below).
  I am currently in &quot;America/Denver&quot;.</p>
  <p>My data was previously plotted so that everything was shifted 6 hours <em>back</em> but I was able to align that properly on the x-axis, but now the bounds/limits of the x-axis are still a problem.</p>
  <pre><code>date_format &lt;- function(format = &quot;%b %d - %H:%M&quot;) {function(x) format(x, format)}
  
  lims &lt;- as.POSIXct(strptime(c(&quot;2021-05-04 08:00:00&quot;,&quot;2021-05-08 08:00:00&quot;), format = &quot;%Y-%m-%d %H:%M&quot;))
  
  combo_ch1short &lt;- ggplot(data = data_combo_ch1short, aes(x = DateTime, y = Z.kOhm, color = probe.pair.name)) + 
   scale_x_datetime(labels = date_format(), limits = lims, date_breaks = &quot;12 hours&quot;) + ...
  </code></pre>
  <p>Sorry, pretty new to this. Any help is GREATLY appreciated!</p>
  <p>Edit:</p>
  <p>data_combo_ch1short:</p>
  <pre><code>Time        probe.pair.name      DateTime              Z.kOhm 
  1617890878     ch_1_ch_2         2021-04-12 17:52:32   5228.69
  1617890878     ch_1_ch_3         2021-04-12 17:52:32   5031.88
  1618251752     ch_1_ch_2         2021-04-12 18:22:32   4089.37
  1618251752     ch_1_ch_3         2021-04-12 18:22:32   4231.90    
  ...         
  </code></pre>