Healthy in cold weather, say (4)
I believe the answer is:
hale
'healthy' is the definition.
(similar in meaning)
'cold weather say' is the wordplay.
'cold weather' becomes 'hail' (I've seen this before).
'say' shows a homophone (sound like).
'hail' sounds like 'HALE'.
'in' acts as a link.
(Other definitions for hale that I've seen before include "Strong and healthy" , "Healthy and robust" , "Healthy and hearty" , "Well" , "Showing vigorous good health" .)