Here's a working version. I changed the temperature ranges slightly to take into account unlimited decimal places and the possibility of temperatures under 15. 
use strict;
use warnings;

my $rows = 5;
my @temps = ('mild','warm','very warm','hot','very hot','extremely hot
+');
my ($range, $lrange, $start, $c, @data, @results);

# Creating nested arrays with data
while (<DATA>) { chomp; push @data, [split(/ /)]; }

$lrange = -1;
for (@data) {
    $range = getrange(@$_[1]);
    if ($range == $lrange) {
        if (++$c == $rows) {
            push (@results, [$start, @$_[0], $temps[$range]]);
            $lrange = -1; $c = 0;
        }
    }
    else {
        $start = @$_[0]; $lrange = $range; $c = 1;
    }
}

# Printing results, tab delimited
for (@results) { print join("\t", @$_) . "\n"; }

sub getrange {
    return 5 if $_[0] >= 40;
    return 0 if $_[0] < 20;
    return int($_[0] / 5 - 3);
}

__DATA__
1-1-2004 33.95
2-1-2004 30.34
3-1-2004 31.50
4-1-2004 32.50
5-1-2004 33.50
6-1-2004 90.00
7-1-2004 51.45
8-1-2004 52.56
9-1-2004 56.23
10-1-2004 50.54
11-1-2004 52.43

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In reply to Re: Searching in an array of arrays by TedPride
in thread Searching in an array of arrays by perl_seeker

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