Protest loudly at the weather (7)
I believe the answer is:
thunder
'weather' is the definition.
(thunder is a type of weather)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for thunder that I've seen before include "Booming noise after lightning" , "What comes with lightning" , "Booming noise from the heavens" , "Heavenly claps?" , "Reverberate" .)