It's said, morning moisture anticipated (3)
I believe the answer is:
due
'anticipated' is the definition.
(similar in meaning)
'it's said morning moisture' is the wordplay.
'it's said' indicates a 'sounds like' (homophone) clue.
'morning moisture' becomes 'dew' (moisture on the ground early in the morning).
'dew' is a homophone of 'DUE'.
(Other definitions for due that I've seen before include "...more than one there [ROME]" , "Outstanding" , "Rightful" , "Deserved or unpaid" , "Owed, or payable immediately" .)