How to find out what is using TEMP during night?

Hi, we have a few reports that are created on a Data Warehouse database overnight (approx. 3-7am). During the last few days these reports have failed with ORA-1652: unable to extend temp segment by 128 in tablespace TEMP. How can we find out which session/sql is using the TEMP tablespace during the night? We have tried looking at the STATS and AWR but this doesn't show TEMP usage. Do we have to submit a job to check temp tablespace every ? minutes? Is there an easier way?
Thank you. Regards Sheryl

If you have limited set of reports you can quickly find the query which is using group by, order by, or distinct.

or ... why don't you get help from your reports admin to identify which report is failed and then ask him/her to extract the query using for that report.

Thanks,