Clerk of the course Gary Thompson said Friday's race programme, which includes the Senior race, has been delayed by two hours.
The final day of racing will begin with the TT ZERO for electric machines at 12:15 BST before the second sidecar race at 13:15.
The TT festival's main six-lap Senior for Superbikes will start at 15:15.
No racing was held on Thursday after torrential rain fell around the island leading to the second Supersport race being axed from this year's schedule.
The final day of racing at the Isle of Man TT has been delayed to give the course further time to dry.