Problem with WP_User_Query when ‘meta_value’ is an array

Here is what I did and it worked for me:

$current_day = date("d");
$current_month = date("m");

$args = array(
'orderby' => 'login',
'order' => 'ASC',
);

// The Query
$user_query = new WP_User_Query( $args );

// User Loop
if ( ! empty( $user_query->results ) ) {
    foreach ( $user_query->results as $user ) {

        if ( $user->birth_date['day'] == $current_day &&
             $user->birth_date['month'] == $current_month )

         { echo '<span>' . $user->display_name . '</span>'; }   

    }
}