my @sorted_by_temp_asc = sort { tricky_sort($a,$b,'T') } @data;

sub tricky_sort {
   my ($A, $B, $field) = @_;
   my %a_dat = map { split('=', $_, 2) } split(',',$A);
   my %b_dat = map { split('=', $_, 2) } split(',',$B);

   return ( $a_dat{$field} <=> $b_dat{$field} );
}