Best approach to create Hot and Trending sections

I am going to implement a Hot and Trending section on a website. I have seen such sections on many popular websites but can't really figure out how exactly this works.

Although I assumed Hot section is most popular posts (based on post views) which I developed by a custom WP_Query. And it works.

$args = array(
    'post_type' => 'post',
    'post_status' => 'publish',
    'meta_key' => 'post_views',
    'orderby' => 'meta_value_num',
    'ignore_sticky_posts' => 1,
    'paged' => $paged,
);
$hot_query = new WP_Query( $args );

But I am stuck on Trending section. What exactly is the idea behind it for creating a custom query.

I want to know what is the best approach to get content in each section. I tried searching on Google for couple of days but could not really find anything useful.

EDIT

My post views function.

function set_post_views( $postID ) {
  if ( is_singular() ) {
    $count_key = 'post_views';
    $count = get_post_meta( $postID, $count_key, true );
    if ( $count=='' ) {
      $count = 0;
      delete_post_meta( $postID, $count_key );
      add_post_meta( $postID, $count_key, '0' );
    } else {
      $count++;
      update_post_meta( $postID, $count_key, $count );
    }
  }
}