use strict;
use warnings;

while (<DATA>) {
    next unless /\S/;
    my ( $sunrise, $sunset ) = get_time($_);
    next unless $sunrise && $sunset;
    printf "Sunrise is: %s Sunset is: %s\n", $sunrise, $sunset;

}

sub get_time {
  my $string = shift;
  return unless $string =~ /sunrise:\s+(\d+:\d+)\s+sunset:\s+(\d+:\d+)/;
  return ( $1, $2 );
}

__DATA__
Aberdeen, Scotland 57 9 N 2 9 W sunrise: 03:12 sunset: 21:08
Adelaide, Australia 34 55 S 138 36 E sunrise: 06:52 sunset: 16:41