echo date('Y-m-d',time())
i get 2012-07-16 ,but when smarty output is
{$smarty.now | date_format : "%Y-%I-%d"}
i get 2012-04-16
I have been sured the time_zone is seted right.
Because %I is hours ... try :
{$smarty.now | date_format : "%Y-%m-%d"}
%m - month as a decimal number (range 01 to 12)