title: Timezone Calculation Issues
body: <p>I am making a countdown timer and I want it to globally countdown to Christmas.  Therefore I have my timestamp value of 1387929600 which is dec 25 00:00:00.  I am adjusting that value according to the different time zones and I am doing it like this:</p>
  
  <pre><code>NSDate *firstDate = [NSDate dateWithTimeIntervalSince1970:1387954801];
  
      NSTimeZone *tz = [NSTimeZone localTimeZone];
  
      int tzInt = [tz secondsFromGMTForDate:firstDate];
  
      int timeDifference = tzInt+1387954801;
  
      xmasDate = [NSDate dateWithTimeIntervalSince1970:timeDifference];
  </code></pre>
  
  <p>I take the <code>firstDate</code> and do <code>secondsFromGMTForDate</code> and then add it to the original timestamp number to get the <code>xmasDate</code> adjusted for time zones.   </p>
  
  <p>This general approach seems to work however the <code>secondsFromGMTForDate</code> is not calculating correctly. </p>
  
  <p>For example when I set my phone to the current time zone it still wants to subtract <code>"-25200"</code> from the timestamp time when it should be zero since its the current time zone.</p>
  
  <p>Am I correct in saying that?  I might be missing something in the calculation and maybe I have to add to the timestamp number but I'm not sure. </p>
  
  <p>Any help would be greatly appreciated.</p>