Celebration ideas for after civil ceremony

My fiancé and I were planning on doing a May 2021 wedding, but the pandemic has really thrown us for a loop so that probably isn’t going to happen. Instead we’re going to do a small civil ceremony in September and have our big wedding down the road when we can. We’re planning on having between 10-20 people there and we’re getting married in a small gazebo in a public park. We’d like to have some small celebration afterwards with the people who came to the ceremony, but we’re stuck on where. Having it at someone’s house isn’t really possible and the weather can be very unpredictable where I live, so being outside without a backup plan isn’t possible either. Any one have any good ideas as to what we could do? Thanks!