title: What format is this date value in?
body: <p>Here's a forecast for London, GB from the <a href="http://openweathermap.org" rel="noreferrer">Open Weather Map</a> in JSON format.</p>
  
  <pre><code>http://api.openweathermap.org/data/2.5/forecast/daily?id=524901
  </code></pre>
  
  <p>Each list item in the JSON has a key within it called <code>dt</code> that looks like <code>"dt":1399626000</code></p>
  
  <p>I haven't done this before, so how do I figure out what format (unix timestamp?) and timezone <code>dt</code> is in (e.g. GMT, UTC), and how to translate the <code>dt</code> into a human-friendly format.</p>