Ordering of posts, 2020 Year showing as next event when should be last

Question

We have some event posted into wordpress which are ordered by date. All works well except when we enter an event for 2020 it comes at the top of the list rather than the bottom. The date is save in the database as "01/24/2020"

All 2019 event are ordered correctly, by day and then month, with next upcoming showing at top of list.

Below if the code for the query. I'm not sure if it the query where the issue is, the database or both. Appreciate any help or advice.

if( $data['items_per_page'] ) {
                        $event_perpage = $data['items_per_page'];
                    }
                    else {
                        $event_perpage = '10';
                    }

                    $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;

                    $args = array(
                        'post_type' => 'event',
                        'posts_per_page' => $event_perpage,
                        'paged' => $paged,
                        'meta_key' => $prefix.'event_date',
                        'orderby' => 'meta_value',
                        'order' => 'ASC'
                    );

                    $wp_query = new WP_Query($args);

                    if($wp_query->have_posts()) :
                        while($wp_query->have_posts()) :
                            $wp_query->the_post(); ?>

                        <?php

                            // Get event date
                            $e_date = get_post_meta($post->ID, $prefix.'event_date', true);
                            $e_date_end = get_post_meta($post->ID, $prefix.'event_date_end', true);
                            if ( $e_date !== '' ) {
                                $event_date_string = $e_date;
                                $event_year = mysql2date( 'Y', $event_date_string );
                                $event_monthM = mysql2date( 'M', $event_date_string );
                                $event_day = mysql2date( 'd', $event_date_string );
                                $event_month = apply_filters('get_the_date', $event_monthM, 'M');
                            }
                            // If no date set
                            else {

                                $event_month = "No Date";
                                $event_day = "00";
                                $event_year = '';

                            }

                            if ( $e_date_end !== '' ) {
                                $event_date_end_string = $e_date_end;
                                $event_year_end = mysql2date( 'Y', $event_date_end_string );
                                $event_monthM_end = mysql2date( 'M', $event_date_end_string );
                                $event_day_end = mysql2date( 'd', $event_date_end_string );
                                $event_month_end = apply_filters('get_the_date', $event_monthM_end, 'M');
                            }

                            // Get event time
                            $e_time = get_post_meta($post->ID, $prefix.'event_time', true);
                            if ( $e_time !== '' ) { $event_time = $e_time; }
                            else { $event_time = __('No time set','qns'); }

                            // Get event location
                            $e_location = get_post_meta($post->ID, $prefix.'event_location', true);
                            if ( $e_location !== '' ) { $event_location = $e_location; }
                            else { $event_location = __('No location set','qns'); }

Thank you.

Answer 1

OK so fixed this by updating the following line from

$output .= 'jQuery(".datepicker").datepicker();';

to

$output .= 'jQuery(".datepicker").datepicker({ dateFormat: "yy-mm-dd" });';

Thank you for all the help