Figured it out through reading the wp_query codex – https://codex.ww.wp.xz.cn/Class_Reference/WP_Query.
Basically all I needed to do was set a variable that captured the page title – which is either Monday, Tuesday, Wednesday, etc – then use the variable in arguments like so:
$title = get_the_title();
$args = array(
‘numberposts’ => -1,
‘post_type’ => ‘activities’,
‘post_status’ => ‘publish’,
‘meta_query’ => array (
array (
‘key’ => ‘day’,
‘value’ => $title,
‘compare’ => ‘IN’
)
) );
It’s always nice to work it out by yourself!
John