add_action( 'woocommerce_after_shop_loop_item', 'rs_show_weights', 9 );

function rs_show_weights() {

    global $product;
    $weight = $product->get_weight();

    if ( $product->has_weight() ) {
        echo '<div class="product-meta"><span class="product-meta-label">Weight: </span>' . $weight . get_option('woocommerce_weight_unit') . '</div></br>';
    }
}