Wet weather is said to be prevalent (8)

I believe the answer is:

reigning

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'prevalent' is the definition.
(thesaurus)

'wet weather is said to' is the wordplay.
'wet weather' becomes 'rain' (I've seen this before).
'is said' shows a homophone (sound like).
'to' becomes 'ing' (I can't explain this - if you can you should believe this answer much more).
'rain' sounds like 'reign'.
'reign'+'ing'='REIGNING'

'be' acts as a link.

Can you help me to learn more?

(Another definition for reigning that I've seen is " Ruling over like a sovereign".)

I've seen this clue in The Globe and Mail.

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