The best thing to do is check the website https://grandfather.com/. Also last I saw you have to make a reservation to enter the park.
You need to make a reservation and you can do it online.
I was fortunate to get a shred of signal by the gate and made my reservation there for 30 minutes later. Unless there are weather issues, they should be open just about every day. The museum is not, but everything else was 3 weeks ago...
I agree with Nathaniel. As of 2 weeks ago you needed a reservation to get your car in. If you plan to park outside the park and hike in, it's free and you don't need a reservation.
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