Yesterday, the Cleveland Metroparks Zoo announced that this year's Asian Lantern Festival will be extended until September 20th. The event was only supposed to run until August 23rd. Because of limited ticket availability to keep zoo capacity down for the event, they have ultimately decided to extend it for another month for those who would like to go.
I haven't been to the festival yet this year, but from what I've heard, it's actually been really easy to maintain your social distance and stay away from others. Yeah, you'll probably see clusters of people taking photos of the same thing, but the best way to avoid that would be to just go around them and move on. So if you want to go, make sure you get your tickets! September 20th will be here before you know it.