Determining, on meeting (8)
I believe the answer is:
settling
This clue might be a double definition.
'determining' is the first definition.
('settle' can be a synonym of 'determine')
'meeting' is the second definition.
The definition and answer can be both related to natural events as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'on' acts as a link.
Can you help me to learn more?
(Other definitions for settling that I've seen before include "Sorting out" , "Coming to rest or paying a bill" , "Coming to mutually agreeable terms" , "Gradually sinking to a lower level" , "Coming to terms or becoming established" .)