my %months = (
	FEB => { W1 => 11.14,
	         W2 => 11.22, },
	MAR => { W1 => 33.17,
	         W2 => 44.44, },
	APR => { W1 => 55.00,
	         W2 => 66.66, },
);
my %limits = (
	FEB => { W1 => { L1 =>  11,    U1 =>  12.05 },
	         W2 => { L1 =>  13.06, U1 =>  13.06 }, },
	APR => { W1 => { L1 =>   1,    U1 =>  20    },
	         W2 => { L1 =>  33,    U1 =>  13.02 }, },
	MAR => { W1 => { L1 => -12.05, U1 => -14.0  },
	         W2 => { L1 =>  22.0,  U1 => -13.02 }, },
);

##</code><code>##

for my $mon ( sort keys %months ) {
	for my $week ( sort keys %{ $months{$mon} } ) {
		if ( exists $limits{$mon} && exists $limits{$mon}{$week} ) {
			my $value = $months{$mon}{$week};
			my $upper = $limits{$mon}{$week}{U1};
			my $lower = $limits{$mon}{$week}{L1};
			printf "%6.2f <= %6.2f <= %6.2f - ",
			        $lower,  $value,  $upper;
			if ( $value >= $lower && $value <= $upper ) {
				print "OK\n";
			}
			else {
				print "NOT ok\n";
			}
		}
		else { warn "No limits for month $mon / week $week\n" }
	}
}

##</code><code>##

  1.00 <=  55.00 <=  20.00 - NOT ok
 33.00 <=  66.66 <=  13.02 - NOT ok
 11.00 <=  11.14 <=  12.05 - OK
 13.06 <=  11.22 <=  13.06 - NOT ok
-12.05 <=  33.17 <= -14.00 - NOT ok
 22.00 <=  44.44 <= -13.02 - NOT ok