Great question, and honestly one I hear a lot from people who live in real winter country. The short answer is that a quality park bench is designed to take a serious snow load, and the legs usually won’t bend just because snow piles up on the seat. What you’re really watching out for is a cheap bench with thin metal, poor welds, or a design that was never meant for outdoor winter exposure.
Here’s the simplest way to think about it. Snow is heavier than it looks, especially wet, heavy snow. A cubic foot of wet snow can weigh anywhere from 15 to 20 pounds or more. If a bench seat is about six feet long and two feet deep, and you get two feet of settled snow on it, that could be a few hundred pounds sitting on the frame. That sounds scary, but the load is spread across the whole seat. Most commercial park benches with steel or cast iron legs are built to handle 500 to 750 pounds of distributed weight without a problem. The legs are usually the strongest part because they’re meant to take vertical compression, not just a person sitting on one end.
Where you might see bending is with very cheap tubular aluminum or thin-gauge steel benches, especially if the legs are long and have no cross brace. Those can flex under a heavy load, and if one leg is already dented or rusted near the bottom, a big snow load could make it worse. But even then, the seat frame or the welds often fail before the legs fold. So unless you bought the lightest budget bench you could find, I wouldn’t stay up at night worrying about the legs bending.
The bigger risks in heavy snow are usually rust, freeze-thaw cycles, and water getting into joints. If water seeps into small cracks or bolt holes and then freezes, it can expand and cause damage. That’s a slower process, but it’s much more common than a leg bending from snow weight.
If you want to play it safe, there are a few easy things you can do. First, check what the manufacturer lists as the bench’s weight capacity or whether it’s rated for commercial outdoor use. Second, if you’re expecting a really wet, heavy storm, just brush the snow off once or twice during the storm. You don’t need to keep it perfectly clear, but removing the worst of the build-up takes a lot of stress off the frame. Third, check the bolts and joints each spring. Tighten anything that’s loose, and touch up any scratches or rust spots before next winter.
So do park bench legs bend in heavy snow? On a decent bench, no. On a flimsy one, maybe, but it’s still not the most likely failure point. If you have a solid steel or cast iron bench, it should hold up just fine. I’d only start to worry if the bench already feels wobbly, has visible rust holes, or the legs are noticeably thin metal.