Average temperature, as intended (5)
I believe the answer is:
'as intended' is the definition.
(I've seen this before)
'average temperature' is the wordplay.
'average' becomes 'mean' (type of average).
'temperature' becomes 't' (abbreviation).
(Other definitions for meant that I've seen before include "Intended, had in mind" , "Had as purpose or design" , "Had as intention or purpose" , "Denoted" , "designed" .)