ai0013
Subscriber
One way is before running the case, activate the data sampling for time-statistics under the calculation options. Define your report definitions by selecting unsteady-statistics/mean temperature and run. Fluent will perform the time-averaging during the calculation.
Other way is to post-process your existent collection of .dat files, but It may be more tedious to open, close and reopen them. Perhaps a journal with auto-execution commands can help.