Round POW’s dancing in heavy rain (8)
I believe the answer is:
downpour
'heavy rain' is the definition.
(I've seen this before)
'round pow's dancing' is the wordplay.
'dancing' indicates anagramming the letters.
'round'+'pow'='roundpow'
'roundpow' with letters rearranged gives 'DOWNPOUR'.
'in' is the link.
(Other definitions for downpour that I've seen before include "falling water" , "Heavy shower" , "cats and dogs?" , "Big fall makes" , "Torrent" .)