How to prevent WordPress from loading the jQuery library at the top of the page

When I build themes, I also like to make the WordPress header as clean as possible and then reconstruct it to my own liking. The code below is excessive for your question, but it might help you with other ‘WordPress inserted code’ in the future. The key snippet of code you are looking for is

wp_deregister_script('jquery'); 
wp_register_script('jquery', '', '', '', true);

Put this in your functions.php file.

My whole WordPress header cleanup:

/* =Clean up the WordPress head
------------------------------------------------- */

    // remove header links
    add_action('init', 'tjnz_head_cleanup');
    function tjnz_head_cleanup() {
        remove_action( 'wp_head', 'feed_links_extra', 3 );                      // Category Feeds
        remove_action( 'wp_head', 'feed_links', 2 );                            // Post and Comment Feeds
        remove_action( 'wp_head', 'rsd_link' );                                 // EditURI link
        remove_action( 'wp_head', 'wlwmanifest_link' );                         // Windows Live Writer
        remove_action( 'wp_head', 'index_rel_link' );                           // index link
        remove_action( 'wp_head', 'parent_post_rel_link', 10, 0 );              // previous link
        remove_action( 'wp_head', 'start_post_rel_link', 10, 0 );               // start link
        remove_action( 'wp_head', 'adjacent_posts_rel_link_wp_head', 10, 0 );   // Links for Adjacent Posts
        remove_action( 'wp_head', 'wp_generator' );                             // WP version
        if (!is_admin()) {
            wp_deregister_script('jquery');                                     // De-Register jQuery
            wp_register_script('jquery', '', '', '', true);                     // Register as 'empty', because we manually insert our script in header.php
        }
    }

    // remove WP version from RSS
    add_filter('the_generator', 'tjnz_rss_version');
    function tjnz_rss_version() { return ''; }