Rule in bad weather, say (5)
I believe the answer is:
reign
'rule' is the definition.
(I know that reign is a kind of rule)
'bad weather say' is the wordplay.
'bad weather' becomes 'rain' (rain is an example of bad weather).
'say' shows a homophone (sound like).
'rain' sounds like 'REIGN'.
'in' acts as a link.
(Other definitions for reign that I've seen before include "Hold sway, rule" , "Monarch's time in the job" , "are unbeatable!" , "Period on the throne" , "Sovereignty" .)