Mysql: Determine size of user-created temp table

Question

I am creating a temp table in mysql. I would like to know the size of the table once it is created, but nothing appears for it using SHOW TABLE STATUS or in information_schema.TABLES. Is there any way to figure this out?

Two queries I have used in the past for something similar have been

SELECT
    table_name AS `Table`,
    round(((data_length + index_length) / 1024 / 1024), 2) `Size in MB`
FROM
    information_schema.tables
WHERE
        table_schema = '<my schema>'
  AND table_name = <my table name>';

and

show table status like '<my table name>';

But both of these return empty results for my temp table.