Short answer: yes, many street benches can stay outside all winter without cracking—but it really depends on the material, the build quality, and how much moisture the bench absorbs. Cold alone is rarely the problem. The real troublemaker is water.
Here is how it works. Rain or snow soaks into tiny pores in the bench. When the temperature drops, that water freezes and expands. After enough freeze-thaw cycles, the material can split, flake, or crack. So the question is not just how cold it gets, but how wet the bench gets and whether it can dry out.
Wood benches are the ones most likely to crack if left outside untreated. Softwoods like pine, fir, and basic construction lumber soak up moisture easily. Once that water freezes, it expands inside the wood and can create small surface cracks or even split the joints. Exposed end grain is usually where the damage starts. But not all wood is equal. Dense hardwoods such as teak, ipe, shorea, white oak, and cedar have natural oils and a tighter grain that resist water absorption. Teak is the gold standard. A good hardwood bench with a penetrating oil or sealer will usually survive winter without serious cracking. A cheap softwood bench? Do not count on it.
Metal benches are a different story. Steel, cast iron, and aluminum are not porous like wood, so they do not trap water inside the metal itself. In normal winter temperatures, even in very cold places, a metal bench frame will not split from freezing. What you need to watch is the finish. Powder coating or paint can develop hairline cracks from thermal expansion and contraction. Once moisture reaches the metal underneath, rust begins. Cast iron and steel should be repainted or touched up before winter. Aluminum is a great low-maintenance option because it does not rust.
Plastic and recycled plastic benches are where winter gets less scary. High-density polyethylene and polywood-style recycled plastic do not absorb water, so freeze-thaw cycles do not really crack them. They are a solid choice if you want a leave-it-out-all-winter bench. Cheap PVC or brittle plastic can become more rigid in extreme cold and might crack if hit hard, but normal use is usually fine.
Concrete and stone benches are strong but porous. If water seeps into small voids and freezes, the surface can spall or crack over years. A high-quality concrete bench with a good sealer and proper drainage usually handles winter okay. But if it sits in a puddle or already has hairline cracks, frost will make it worse.
So can you leave your street bench out all winter? Yes, if it is made from teak, cedar, white oak, aluminum, or recycled plastic, if it is sealed or oiled when needed, and if water can drain off instead of pooling. No, or at least not without risk, if it is cheap untreated softwood, already cracked, sitting in standing water, or made from unsealed concrete in a wet freeze-thaw climate.
My honest advice is to buy the right bench for your climate. If you already own a wooden bench, apply a good outdoor wood sealer in fall, tighten the bolts, and keep the legs from sitting in mud or ice. A breathable cover helps too. If you are buying new and want to leave it outside every winter without worrying about cracks, choose teak, aluminum, or recycled plastic.
So yes, many street benches can absolutely survive winter outside without cracking. The ones that last are usually built for it. Cheap, untreated wood left wet and frozen all season is the one that gives up first.