Choosing the right seating material for an outdoor bench in a four-season climate is a balance between comfort, durability, and low maintenance. The quest isn't for a single "perfect" material, but for a high-performance system. The foundation of comfort lies in the cushioning. High-resiliency, high-density foam is king. It provides excellent support, resists permanent sagging, and dries quickly. Pair this with a top-tier outdoor fabric for true four-season comfort.
For the fabric, solution-dyed acrylics like Sunbrella are the gold standard. They are inherently UV-resistant, so colors won't fade, highly water-repellent, and resist mold and mildew. Synthetic wickers (HDPE or resin) are another superb choice, offering a textured look that is weatherproof and easy to clean. For a more natural feel, tightly woven polyester or olefin fabrics with a protective coating perform very well.
The bench frame material also contributes. Teak or powder-coated aluminum frames with a slight contour or backrest angle are more comfortable than flat, hard surfaces. For cushionless options, thermally modified wood stays cooler in summer and warmer in winter than untreated wood or metal.
Your comfort strategy should also include maintenance: use quick-dry foam inserts, store cushions in harsh winter weather, and clean fabrics regularly. Ultimately, the most comfortable seat is a supportive foam cushion wrapped in a solution-dyed acrylic fabric, placed on a sturdy, angled bench—a combination designed to deliver comfort through sun, rain, and snow.