Uber limits you to 30 days in advance when selecting a pickup date. This is to simplify things on their end and make sure they don't have people booking dates way in the future and then forgetting about them. You may notice when booking with the app that you can select any date in the future. But fair warning: The menu will revert it back to one month out if you tap on a date that's too far ahead. That's another reason why it's always important to double check the date before scheduling a ride.