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

my %some_hash = (
		   sunny => .63,
           cloudy => .17,
           rainy => .2
		   );

my ($max) = sort {$some_hash{$b}<=>$some_hash{$a}} keys %some_hash;
print $max." :: ".$some_hash{$max}."\n";

outputs:   sunny :: 0.63