Perl Heat Index Calculation

heat-index.pl

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

my $tf = $ARGV[0]; # Temperature in degrees Fahrenheit
my $rh = $ARGV[1]; # Abs. Relative Humidity

my $hi = -42.379 + 2.04901523 * $tf 
         + 10.14333127 * $rh 
         - 0.22475541 * $tf * $rh 
         - (6.83783 * 10**(-3)) * ($tf**(2)) 
         - (5.481717 * 10**(-2)) * ($rh**(2)) 
         + (1.22874 * 10**(-3)) * ($tf**(2)) * $rh 
         + (8.5282 * 10**(-4)) * $tf * ($rh**(2)) 
         - (1.99 * 10**(-6)) * ($tf**(2)) * ($rh**(2));

print $hi . "\n";

exit;

__END__

http://en.wikipedia.org/wiki/Heat_index
http://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml