$ ncal -w 1 2016
    Januar 2016       
Mo     4 11 18 25   
Di     5 12 19 26   
Mi     6 13 20 27   
Do     7 14 21 28   
Fr  1  8 15 22 29   
Sa  2  9 16 23 30   
So  3 10 17 24 31   
   53  1  2  3  4   

##</code><code>##

use warnings;
use strict;
use DateTime;

my $dt = DateTime->new(year=>2015,month=>12,day=>30);
for (1..10) {
	print $dt->ymd, " week ",$dt->week_number,"\n";
	$dt->add(days=>1);
}

__END__

2015-12-30 week 53
2015-12-31 week 53
2016-01-01 week 53
2016-01-02 week 53
2016-01-03 week 53
2016-01-04 week 1
2016-01-05 week 1
2016-01-06 week 1
2016-01-07 week 1
2016-01-08 week 1