I've never seen the patio closed.
No chance of rain according to the forecast, so it will be open. But could be a long wait, they don't take reservations for the patio. You may consider going early (5-6) or late (9-10) to minimize the wait.
But even the wait isn't bad. They'll give you a wireless buzzer so you can sit at a nearby slot or VP machine to pass the time. Or grab a drink at the sportsbook bar while you wait.