I reworked your snippet code. It is probably not exactly what you need but I hope you can find useful details in it.

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

my @month = qw/JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC/;

my $hash = {
  2 => { W1 => 10.14,
         W2 => 11.22,
  },
  3 => { W1 => 33.17,
         W2 => 44.44,
  },
  4 => { W1 => 55.00,
         W2 => 66.66,
  },
};

my $lim = {
  2 => { W1 => { L => 11,    U => 14 },
         W2 => { L => 13,            },
  },
  4 => { W2 => { L => 13.02, U => 15 },
  },
};


for my $month ( sort keys %$hash ) {
  print "$month[$month-1]:\n";
  for my $week ( sort keys %{$hash->{$month}} ) {

    my $lower = defined $lim->{$month}->{$week}->{L} ? $lim->{$month}-
+>{$week}->{L} : 0;   # min value
    my $upper = defined $lim->{$month}->{$week}->{U} ? $lim->{$month}-
+>{$week}->{U} : 999; # max value
    my $value = $hash->{$month}->{$week};

    my $below = ($value < $lower) ?  sprintf('%6.2f', $value) : '';
    my $above = ($value > $upper) ?  sprintf('%6.2f', $value) : '';
    my $in    = ($value >= $lower and
                 $value <= $upper) ? sprintf('%6.2f', $value) : '';

    printf "    %s %6.6s <%6.2f> %6.6s <%6.2f> %6.6s\n",
        $week, $below, $lower, $in, $upper, $above;
  }
}
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