++ your use of values. But you missed (your own) trick with grep in your procedural version:

my ($rating, $bwurl) = 0;
foreach my $subhash ( grep $_->{Season} == $seasonnum, values %$hdata 
+) {
    if( $subhash->{Rating} > $rating){
         $rating = $subhash->{Rating};
         $bwurl  = $subhash->{BannerPath};
    }
}
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