You can do this with the pre_get_posts
action. pre_get_posts
fires after the query variable object is created, but before the actual query is run. So you won’t suffer performance penalties by running multiple unnecessary queries.
In your functions.php
:
add_action('pre_get_posts','xx_taxnomy_query');
function xx_taxnomy_query($query) {
if ($query->is_main_query() && ! is_admin() && $query->is_tax('your_taxonomy')) {
$query->set('order', 'asc');
return;
}
}