You can use a Client Task Schedule for this. Under Jobs and Tasks you can right-click where you'd normally create a new task, but choose New > Client Task Schedule. This will let you run the task on whatever schedule you like, but it's now a policy instead of a task. This will run on schedule even if you have no connection to a Task Server.
The only downside is that you can only have one task per Client Task Schedule, but most of the time that will suffice.