sort.php

<?php

$repeater = get_field('the_date');

foreach( $repeater as $i => $row ) :

	$column_id[ $i ] = $row['the_date'];

endforeach; 

array_multisort( $column_id, SORT_ASC, $repeater );

$month = '';

foreach( $repeater as $row ) :

	$date = DateTime::createFromFormat('Ymd', $row['the_date']);

	if ($month != $date->format('F')) : ?>

	<ul>
		<li><?php echo $date->format('F'); ?></li>
		<li><?php echo $row['name']; ?></li>
	</ul>

<?php else : ?>
	
	<ul>
		<li><?php echo $date->format('m/d'); ?></li>
		<li><?php echo $row['name']; ?></li>
	</ul>
	
	<?php endif; ?>
<?php endforeach; ?>