groupby="day" only shows day and month, no year

Roxanne!

Glad you like it.

Add this code to the functions.php of your theme:

/**
 * Changes the date format for the day group header.
 *
 * @param	string	$group_header	The default group header.
 * @param 	string	$day			The day in <code>YYYY-MM-DD</code> format.
 * @return	string					The new group header.
 */
function roxanne_change_group_day_date_format( $group_header, $day ) {
	return date_i18n( 'l d F Y',strtotime( $day ) );
}
add_filter('wpt_listing_group_day', 'roxanne_change_group_day_date_format');

Thanks Jeroen!

I added it to the functions.php, but this is the warning I get:

Warning: Missing argument 2 for roxanne_change_group_day_date_format() in /home/patrickn/public_html/wp-content/themes/pique/functions.php on line 329

Do you know why..?

Thanks again!

This should fix that:

/**
 * Changes the date format for the day group header.
 *
 * @param	string	$group_header	The default group header.
 * @param 	string	$day			The day in <code>YYYY-MM-DD</code> format.
 * @return	string					The new group header.
 */
function roxanne_change_group_day_date_format( $group_header, $day ) {
	return date_i18n( 'l d F Y',strtotime( $day ) );
}
add_filter('wpt_listing_group_day', 'roxanne_change_group_day_date_format', 10, 2);

Awesome!! Thanks so much!