#!/usr/bin/env perl

use strict;
use warnings;
use Time::Piece::Plus;

my $today = localtime()->today;
my $date = localtime()->strptime("2015-04-20", '%Y-%m-%d');

print "Date: $date tzoffset=", $date->tzoffset, "\n";
print "Today: $today tzoffset=", $today->tzoffset, "\n";
print "Diff: ", ($date - $today), "\n";

##</code><code>##

Date: Mon Apr 20 00:00:00 2015 tzoffset=-25200
Today: Mon Apr 20 00:00:00 2015 tzoffset=-25200
Diff: 0

##</code><code>##

$ cpanm Time::Piece
Time::Piece is up to date. (1.29)
$ cpanm Time::Piece::Plus
Time::Piece::Plus is up to date. (0.05)
$ perldoc -t Time::Piece | grep -i zone
        $t->tzoffset            # timezone offset in a Time::Seconds object
$ perldoc -t Time::Piece::Plus | grep -i zone
$