Temporary, during winter improvements (7)
I believe the answer is:
interim
'temporary' is the definition.
(similar in meaning)
'during winter improvements' is the wordplay.
'during' indicates the answer is hidden within the clue.
'INTERIM' is hidden within 'winter improvements'.
(Other definitions for interim that I've seen before include "Meanwhile" , "Stopgap" , "Meantime - provisional" , "not there for ever" , "Temporary - provisional" .)