#!/usr/bin/perl
use warnings;
use strict;

use Time::Piece;

$ENV{TZ} = 'Europe/Berlin';
print 'Time::Piece'->VERSION, " $]\n";

for my $ts (qw( 2016-09-25 2016-10-31 )) {
    $_ = $ts . 'T12:00:00';
    my $datetime = 'Time::Piece'->strptime($_, '%Y-%m-%dT%H:%M:%S');
    my $utc_offset = $datetime->strftime('%z');
    chomp( my $system_offset = qx{ date +%z -d $_ } );
    printf "%s - %s - %s - %s\n", $datetime, $utc_offset, $system_offset, $datetime->tzoffset;
}

__END__
1.20_01 5.018002
Sun Sep 25 12:00:00 2016 - +0100 - +0200 - 0
Mon Oct 31 12:00:00 2016 - +0100 - +0100 - 0

1.31 5.025007
Sun Sep 25 12:00:00 2016 - +0000 - +0200 - 0
Mon Oct 31 12:00:00 2016 - +0000 - +0100 - 0