tem - por - RER - illy. Emphasis is on the RER.

/ˈtem.pə.rer.əl.i/ is how I would say it. The stress falls on the /rer/. One of the most important things in pronunciation of complex words is the schwa, /ə/. Using it will help you to pronounce things smoothly—this is precisely why native speakers simplify so many vowel sounds to schwa's instead.