Como obter N dias a partir de hoje em PHP
//Simple method how to get the date of tomorrow, yesterday, etc. is to use:
$tomorrow = date( "Ymd", strtotime( "+1 days" ) );
$dayaftertomorrow = date( "Ymd", strtotime( "+2 days" ) );
$yesterday = date( "Ymd", strtotime( "-1 days" ) );
Just Make It Global