If comfort is the main goal, I’d put natural wood at the top of the list—specifically teak, cedar, or white oak. A well-built wooden bench stays closer to air temperature than metal or stone, so it won’t scorch your legs in summer or feel like an ice block in winter. Teak is my personal favorite because its natural oils make it weather-resistant and smooth, giving it a warmer, more forgiving feel for longer sitting sessions.
That said, high-density polyethylene (HDPE) poly lumber is a very close second, and for many people it is the best outdoor bench material. It looks like painted wood but doesn’t splinter, crack, or absorb heat the way metal does. Quality HDPE benches often have contoured seats and rounded edges, which makes a real difference when you plan to sit for an hour rather than five minutes. It is also nearly maintenance-free.
Metal benches—wrought iron, steel, and aluminum—look stylish, but they are usually the least comfortable option for extended sitting. They transfer heat aggressively, becoming hot in direct sun and cold in shade or cool weather. Their hard, flat surfaces also create pressure points quickly. If you love that look, plan on adding thick outdoor cushions.
Stone and concrete are even more extreme. They are durable and weatherproof, but they hold cold, absorb heat, and feel absolutely rigid. They work fine as decorative pieces or short rest stops, but not for long, lingering conversations.
There are also woven options like resin wicker or outdoor rope. These can be surprisingly comfortable because the weave provides a little flex and breathability. Just make sure the frame underneath is aluminum or powder-coated steel, and pair it with a weather-resistant cushion if you want true all-afternoon comfort.
If I had to pick one material for a bench people are actually going to sit on for a while, I would choose a contoured teak or HDPE poly lumber bench with slats that have small gaps for drainage. Shape matters as much as material: a slightly curved seat, a gently angled backrest, and a seat depth around 17 to 18 inches will keep most people comfortable far longer than a flat wooden plank or metal slat bench.
So my honest answer is this: choose wood or quality poly lumber, avoid un-cushioned metal, stone, and concrete, and if possible test the bench for about ten minutes before buying. If the surface temperature feels neutral and your legs do not go numb, you have likely found the right outdoor bench seating comfort.