Say the hail will be followed by rain (4)
I believe the answer is:
aver
'say' is the definition.
(aver means to state or claim something)
'hail will be followed by rain' is the wordplay.
I cannot really see how this works, but
'hail' could be 'ave' (greeting in Latin) and 'ave' is found within the answer.
A single letter 'r' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'the' is the link.
Can you help me to learn more?
(Other definitions for aver that I've seen before include "Vera could declare to be true" , "State firmly, perhaps rave" , "Say firmly, rave if necessary" , "Maintain - assert - allege" , "State decisively" .)