This should work with something like:
$args = array(
'post_type' => 'your_custom_post_type',
'meta_key'=> 'your_field_date',
'orderby' => 'meta_value',
'order' => 'ASC'
);
If you’re are working with the archive page, maybe a best way to do it is modify the main query with the pre_get_posts hook.
For Example:
// in your functions.php
function sort_by_date_my_cpt( $query ) {
if ( is_post_type_archive( 'your_custom_post_type') ) {
$query->set('meta_key', 'your_date_custom_field');
$query->set('orderby', 'meta_value');
$query->set('order', 'ASC');
return;
}
}
add_filter( 'pre_get_posts', 'sort_by_date_my_cpt', 1);
So then, you will to use your WP Loop by default in your archive template.
// in your archive-your_custom_posttype.php or archive.php
<?php if ( have_posts() ) :
<?php while ( have_posts() ) : the_post(); ?>
<?php endwhile; ?>
<?php endif; ?>
