Display the monthly archive links for a specific year.

wp_single_year_monthly_archives.php

<?php
/**
 *  Display the archive links for a single year.
 *
 *  @param   integer  $year        The year you would like to display the archives for
 *  @param   string   $menu_class  Class to add to the ul tag
 *  @return  void
 */
function wp_single_year_monthly_archives($year=null, $menu_class=null) {
    if($year == null) {
        $year = date('Y');
    }
    $months = range(1,12);
    $monthly_posts = array();
    foreach ( $months as $month ) {
        $posts_for_month = get_posts(array(
            'year' => $year,
            'monthnum' => $month
        ));
        $monthly_posts[$month] = $posts_for_month;
    }
    $classes = ($menu_class)?' class="'.$menu_class.'"':'';
    echo '<ul'.$classes.'>';
    foreach ( $monthly_posts as $month => $posts ) {
        $time = mktime(0, 0, 0, $month);
        $month_name = strftime("%B", $time);
        if ($posts) {
            echo '<li><a href="' .get_month_link($year, $month). '">' .$month_name. '</a></li>';
        }
    }
    echo '</ul>';
    wp_reset_query();
}