Great question! Whether a park bench is slippery when wet really depends on the material it's made from. Most traditional wooden park benches—especially those treated with a smooth, glossy varnish or paint—can become quite slick after rain. The water forms a thin layer on the surface, reducing friction just like on a wet deck.
On the other hand, many modern benches use materials like recycled plastic with a textured finish, powder-coated metal with a gritty sand-like coating, or even rubberized strips. These are designed specifically to stay grippy even in damp conditions. For example, benches with slatted wooden or composite boards often have natural drainage grooves that help water run off, reducing slipperiness.
If you're worried about slipping, look for benches labeled as "textured," "non-slip," or "rubber-top." Municipal parks in rainy climates frequently install benches with a sanded or pebbled surface finish. And if you're installing your own, opt for composite materials or apply a non-slip deck tape to the seat area.
In short: yes, some benches are non-slip when wet—but not all of them. Plain wood or smooth metal is risky, while textured composites and rubber-coated benches give you much better footing.