I am hoping somebody can give me any hints or directions to my problem…although I ve search the forum i ve not come across to any solution to my problem…

There it goes: I ve done a digital temperature controller, and everything works fine, but I need to implement a new functionality and I really don’t know how…:
I am constantly reading the temperature in one spot and have to estimate the temperature in the product ( for that I use a kind of offset temp value) but the problem itself is that where i read the temperature it fluctuates much more than in the product (because of the thermo mass of the product) so I need to show a temperature that it is something like an average value with least variations possible…
I guess I could use an array of temperature, drop the top and the end values and calculate the medium…but is here any easier way ? I really don’t want to re-write some big parts of the code  ….
I also was working around some digital filter like the concept : temp_med = (20* temp_now + 80*temp_old )/100 , ETC …but I really was hoping something to discover something simple …
Any help from the pros ?

Thanks a lots, I am really feeling lost…