I dealt with DateTime recently, and I have great respect for it. The author understands the complexities of data and time arithmetic and does a good job of preventing you from shooting yourself in the foot. 

use strict;
use warnings;

use DateTime qw( );

my $today = DateTime->today( time_zone => 'local' );

my $xmas = $today->clone()->set_month( 12 )->set_day( 25 );
if ( $xmas < $today ) {
   $xmas->add( year => 1 );
}

my $days = $xmas->delta_days( $today )->in_units( 'days' );
if    ($days == 0) { print( "Merry Christmas!\n"            ); }
elsif ($days == 1) { print( "Christmas is tomorrow!\n"      ); }
else               { print( "Christmas is in $days days.\n" ); }

[download]

prints 

Christmas is in 78 days.

[download]

Update: Removed unnecessary $today->set_time_zone( 'floating' );.

In reply to Re: Time / Date Arithmetic Module Recommendations by ikegami
in thread Time / Date Arithmetic Module Recommendations by tomazos

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