Had in mind average temperature (5)
I believe the answer is:
meant
'had in mind' is the definition.
(mean can mean to intend or have in mind)
'average temperature' is the wordplay.
'average' becomes 'mean' (type of average).
'temperature' becomes 't' (abbreviation).
'mean'+'t'='MEANT'
(Other definitions for meant that I've seen before include "intimated" , "Intended, had in mind" , "Deliberate" , "Implied" , "Had as intention or purpose" .)