"msk" => +3*3600, # Moscow

##</code><code>##

    ...
    [
63436863600, #    utc_start 2011-03-26 23:00:00 (Sat)
63549957600, #      utc_end 2014-10-25 22:00:00 (Sat)
63436878000, #  local_start 2011-03-27 03:00:00 (Sun)
63549972000, #    local_end 2014-10-26 02:00:00 (Sun)
14400,
0,
'MSK',
    ],
    [
63549957600, #    utc_start 2014-10-25 22:00:00 (Sat)
DateTime::TimeZone::INFINITY, #      utc_end
63549968400, #  local_start 2014-10-26 01:00:00 (Sun)
DateTime::TimeZone::INFINITY, #    local_end
10800,
0,
'MSK',
    ],

##</code><code>##

use DateTime::Format::RFC3339 qw( );

my $f = DateTime::Format::RFC3339->new();
say $_->set_time_zone('Europe/Moscow')->hms()
   for
      $f->parse_datetime('2014-09-01T12:00:00Z'),
      $f->parse_datetime('2015-09-01T12:00:00Z');

##</code><code>##

16:00:00
15:00:00