What does your "data variable" look like? If it's like this:
$mydate = "2010-05-12 13:57:01";
You can simply do:
$month = date("m",strtotime($mydate));
For more information, take a look at date and strtotime.
EDIT:
To compare with an int, just do a date_format($date,"n");
which will give you the month without leading zero.
Alternatively, try one of these:
if((int)$month == 1)...
if(abs($month) == 1)...
Or something weird using ltrim, round, floor... but date_format() with "n" would be the best.