wordpress ajax _POST filtering acf checkbox items

I have a working php ajax form, including pulling data from acf. I can't figure how to filter by checked checkbox items. so if a user checks one/multiple items in the form front end, it would match posts with the same field choices checked. It does work for me if i'm using a select dropdown instead of a checkbox items in the form. My checkbox field is 'weather'.

Here is my form:

<form action="<?php echo site_url() ?>/wp-admin/admin-ajax.php" method="POST" id="filter">
    <?php
        $weather_values = get_field('weather');
        if( $weather_values ): ?>
            <?php  foreach( $weather_values as $weather ): ?>
                <input type="checkbox" name="<?php echo $weather; ?>"><?php echo $weather; ?> 
            <?php endforeach;  ?>
        <?php endif; 
    ?>
    <button>Apply filter</button>
    <input type="hidden" name="action" value="myfilter">
</form>

Here is js:

jQuery(function($){
    $('#filter').submit(function(){
        var filter = $('#filter');
        $.ajax({
            url:filter.attr('action'),
            data:filter.serialize(), // form data
            type:filter.attr('method'), // POST
            beforeSend:function(xhr){
                filter.find('button').text('Processing...'); // changing the button label
            },
            success:function(data){
                filter.find('button').text('Apply filter'); // changing the button label back
                $('#response').html(data); // insert data
            }
        });
        return false;
    });
});

Here is the functions.php

//ajax form submit function
add_action('wp_ajax_myfilter', 'form_filter_function'); // wp_ajax_{ACTION HERE} 
add_action('wp_ajax_nopriv_myfilter', 'form_filter_function');

function form_filter_function(){

    // create $args['meta_query'] array if one of the following fields is filled
    if( isset( $_POST['weather'] ) && $_POST['weather'] == 'on'  )
        $args['meta_query'] = array( 'relation'=>'AND' ); 

    if( isset( $_POST['weather'] )  )
        $args['meta_query'][] = array(
        'key' => 'weather',
        'value' => $_POST['weather'],
        'compare' => 'LIKE'
    );


    $query = new WP_Query( $args );

    if( $query->have_posts() ) :
        while( $query->have_posts() ): $query->the_post();
            echo '<h2>' . $query->post->post_title . '</h2>';
        endwhile;
        wp_reset_postdata();
    else :
        echo 'No posts found';
    endif;

    die();
}

So right now doesn't matter what I check or if I even check something, all posts are showing.