It's there for anybody to win! (4)
I believe the answer is:
open
'win' is the definition.
The definition and answer can be both related to natural events as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for open that I've seen before include "This championship includes both professional and amateur golfers" , "still in debate" , "Not closed or secret" , "Overt" , "Honest - frank" .)