use strict;
use warnings;

while (<DATA>) {
    my ( $sunrise, $sunset ) = get_time($_);

    print "Sunrise is:", ${$sunrise}, "Sunset is:", ${$sunset}, "\n";

}

sub get_time {
    my ($string) = @_;

    my ($sunrise, $sunset);
    $string =~ /sunrise:\s+(\d+:\d+)(?{ $sunrise = $^N})
\s+sunset:\s+(\d+:\d+)(?{$sunset = $^N})/x;

    return ( \$sunrise, \$sunset );

}

__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