Banks on getting temperature right inside trousers (7)
I believe the answer is:
strides
'trousers' is the definition.
(slang for trousers)
'banks on getting temperature right inside' is the wordplay.
'banks' becomes 'sides' ('side' can be a synonym of 'bank').
'on getting temperature' becomes 't' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'right' becomes 'r' (common abbreviation).
'inside' indicates putting letters inside.
't'+'r'='tr'
'sides' enclosing 'tr' is 'STRIDES'.
(Other definitions for strides that I've seen before include "Walks fast" , "Walks with long steps" , "Takes great steps" , "Daks" , "footsteps" .)