Unfit for salting at the wrong time of the year (12)
I believe the answer is:
unseasonable
'unfit' is the definition.
(thesaurus)
'salting at the wrong time of the year' is the wordplay.
I cannot really understand how this works, but
'at' could be 'on' (location) and 'on' is found in the answer.
This explanation may well be incorrect...
'for' is the link.
Can you help me to learn more?
(Other definitions for unseasonable that I've seen before include "Odd for the time of year" , "(Of weather) unusual for the time of year" .)