One under instruction to make a stand about wet weather (7)
I believe the answer is:
trainee
'one under instruction' is the definition.
(I've seen this before)
'a stand about wet weather' is the wordplay.
'a stand' becomes 'tee' (I've seen this before).
'about' is an insertion indicator.
'wet weather' becomes 'rain' (I've seen this before).
'tee' placed around 'rain' is 'TRAINEE'.
'to make' is the link.
(Other definitions for trainee that I've seen before include "Student" , "Person being taught" , "One taking instruction" , "21 [TYRO]" , "One undergoing instruction" .)