Rain maker thundering behind cold front (5)
I believe the answer is:
cloud
'rain maker' is the definition.
(I've seen this in another clue)
'thundering behind cold front' is the wordplay.
'thundering' becomes 'loud' (I've seen this in another clue).
'behind' says to put letters next to each other.
'front' suggests taking the first letters.
The first letter of 'cold' is 'c'.
'loud' after 'c' is 'CLOUD'.
(Other definitions for cloud that I've seen before include "Condensed air vapour" , "It hides the sun" , "E.g. stratus" , "Mass of water droplets" , "Nebula" .)