Possibly astir in numbers due to the wind (7)
I believe the answer is:
mistral
'the wind' is the definition.
(mistral is a kind of wind)
'possibly astir in numbers due' is the wordplay.
'possibly' indicates anagramming the letters.
'in' indicates putting letters inside.
'numbers due' becomes 'ml' (I can't justify this - if you can you should give a lot more credence to this answer).
'astir' is an anagram of 'istra'.
'istra' inserted into 'ml' is 'MISTRAL'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for mistral that I've seen before include "Strong cold dry wind" , "Nice chiller" , "French wind" , "That's a blow" , "Strong north wind of southern France" .)