PHP的日期/时间差异给了我额外的一小时

I'm trying to following code to get the difference in hours between 2 date/time values. The difference should be 47.82, but the result is 48.82. I can't figure out why.

$time1 = '11/03/2013 15:28:00';
$time2 = '11/01/2013 15:39:00';

$hourdiff = round((strtotime($time1) - strtotime($time2))/3600,2);
echo $hourdiff;

Any help is greatly appreciated.

The difference is likely due to daylight saving time.

You could set the dates to UTC which removes this issue.

$time1 = '11/03/2013 15:28:00 UTC';
$time2 = '11/01/2013 15:39:00 UTC';

$hourdiff = round( ( strtotime( $time1 ) - strtotime( $time2 ) ) / 3600, 2 );  

Must be related to daylight saving. I see according to Google daylight saving in the US ends on 2 Nov which could be why. Try this and see if you get the correct result:

$time1 = '11/05/2013 15:28:00 <br/>';
$time2 = '11/03/2013 15:39:00';

Try this...

$diffHours = round(((strtotime($time1) - strtotime($time2)) / 3600),2);

In your equation you are not rounding on total result

Thanks