Healthy weather, we hear (4)
I believe the answer is:
hale
'healthy' is the definition.
(hale can mean fit and healthy)
'weather we hear' is the wordplay.
'weather' becomes 'hail' (hail is a kind of weather).
'we hear' indicates a 'sounds like' (homophone) clue.
'hail' is a homophone of 'HALE'.
(Other definitions for hale that I've seen before include "Showing vigorous good health" , "Healthy and hearty" , "Sound of body" , "Well" , "Strong and healthy" .)