For some reason, each strikes me as a slightly more natural way to do this. If nothing else, it avoids the construction of the key list.

my %h =
(
    sunny   => 0.063,
    cloudy  => 0.017,
    rainy   => 0.020,
    hellish => 0.103,
);

my( $max_key, $max_val ) = each %h;

while ( my($k,$v) = each %h )
{
    $v > $max_val and ($max_key,$max_val) = ($k,$v);
}

print "$max_key => $max_val\n";
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