Perhaps tomorrow Rufus sets cryptic (Saturdays excepted) (6)
I believe the answer is:
future
'perhaps tomorrow' is the definition.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for future that I've seen before include "Time yet to come" , "Verb tense; to come" , "What's yet to come" , "Beyond the present" , "Time still to come" .)