O No! Irishmen race wildly at all times (4,4,2,5)
I believe the answer is:
come rain or shine
'all times' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'o no irishmen race wildly' is the wordplay.
'wildly' indicates anagramming the letters.
'o'+'no'+'irishmen'+'race'='onoirishmenrace'
'onoirishmenrace' with letters rearranged gives 'COME RAIN OR SHINE'.
'at' is the link.
Can you help me to learn more?
(Other definitions for come rain or shine that I've seen before include "Whatever the circumstances" , "Whatever the weather" , "regardless of circumstances" , "no matter what the circumstances may be" .)