也许有更好的优化方法，但我会这样做：

使用WP\\u查询获取所有事件，并按自定义日期字段对其进行排序，循环遍历所有事件并创建一个新的多维数组。在此数组中，我们将按日期（月和年）对所有帖子进行分组。最后，循环遍历我们的新数组，以获取我们提取的日期和事件。代码如下：

<?php
// Edit these values
$custom_post_type  = \'event\';
$custom_date_field = \'event_date\';
$order             = \'ASC\'; // from the oldest to the newest

// query
$the_query = new WP_Query( [
    \'post_type\'      => $custom_post_type,
    \'posts_per_page\' => - 1,
    \'meta_key\'       => $custom_date_field,
    \'orderby\'        => \'meta_value\',
    \'order\'          => $order,
] );

// We are creating new multidimensional array
$all_events = [];

while ( $the_query->have_posts() ) :
    $the_query->the_post();

    $date       = strtotime( get_post_meta( get_the_ID(), $custom_date_field, true ) );
    $month_year = date( "F Y", $date );

    $all_events[ $month_year ][] = $the_query->post;

endwhile;
wp_reset_query();

// And to print this:
foreach ( $all_events as $month_year => $events ) : ?>
    <h3><?php echo $month_year ?></h3>
    <ul>
        <?php 
        /** @var \\WP_Post $event */
        foreach ( $events as $event ) : ?>
            <li><?php
                // post title
                echo $event->post_title;
                // any custom field
                the_field( \'acf_custom_field\', $event->ID );
                ?></li>
        <?php endforeach; ?>
    </ul>
<?php endforeach; ?>

也许有更好的优化方法，但我会这样做：

使用WP\\u查询获取所有事件，并按自定义日期字段对其进行排序，循环遍历所有事件并创建一个新的多维数组。在此数组中，我们将按日期（月和年）对所有帖子进行分组。最后，循环遍历我们的新数组，以获取我们提取的日期和事件。代码如下：

<?php
// Edit these values
$custom_post_type  = \'event\';
$custom_date_field = \'event_date\';
$order             = \'ASC\'; // from the oldest to the newest

// query
$the_query = new WP_Query( [
    \'post_type\'      => $custom_post_type,
    \'posts_per_page\' => - 1,
    \'meta_key\'       => $custom_date_field,
    \'orderby\'        => \'meta_value\',
    \'order\'          => $order,
] );

// We are creating new multidimensional array
$all_events = [];

while ( $the_query->have_posts() ) :
    $the_query->the_post();

    $date       = strtotime( get_post_meta( get_the_ID(), $custom_date_field, true ) );
    $month_year = date( "F Y", $date );

    $all_events[ $month_year ][] = $the_query->post;

endwhile;
wp_reset_query();

// And to print this:
foreach ( $all_events as $month_year => $events ) : ?>
    <h3><?php echo $month_year ?></h3>
    <ul>
        <?php 
        /** @var \\WP_Post $event */
        foreach ( $events as $event ) : ?>
            <li><?php
                // post title
                echo $event->post_title;
                // any custom field
                the_field( \'acf_custom_field\', $event->ID );
                ?></li>
        <?php endforeach; ?>
    </ul>
<?php endforeach; ?>