In very cold weather, action is needed - it will keep child warm (8)

'it will keep child warm' is the definition.
The definition suggests a singular noun which matches the answer.

'in very cold weather action is' is the wordplay.
I cannot really understand how this works, but
'weather' could be 'snow' (snow is a kind of weather) and 'snow' is found in the answer.
'action' could be 'suit' (synonyms) and 'suit' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

'needed' is the link.

Can you help me to learn more?