my (@h,@c);
push @h, $_->{hour} foreach(@{$data});   # no so great
push @c, $_->{count} foreach(@{$data});  # see extremely's comment 
my $new = [ \@h, \@c ];

$gd = $graph->plot($new);                # wrong - see orbital's comment

##</code><code>##

BEFORE:                          AFTER:
$VAR1 = [                        $VAR1 = [
          {                                [  
            'count' => 5,                     1,
            'hour' => 1                       5,
          },                                  2
          {                                ],
            'count' => 2,                  [
            'hour' => 5                       5,
          },                                  2,
          {                                   8
            'count' => 8,                  ]  
            'hour' => 2                  ];
          }
        ];