Is gown and tucks o.k. For 4pm wedding

Depends on the wedding , did the invitation say anything?

You could also ask other guests what they are wearing, and also the venue would say a lot about the attire you need.

It is OK for any wedding. I have married couples on the beach in gown and tux, I have married them in shorts and blue jeans. Weddings are for what the couple wants. Is the 4 pm wedding in a white water raft, a hot air balloon, in a carriage pulled by horses, is it at a swimming pool, in a park, at your home, in a ball room or church.

Weddings are what you ( bride) wants.