The short answer is: it depends entirely on the furniture's materials and construction. High-quality urban outdoor furniture designed for all-weather use can absolutely withstand being left outside through rain and snow. The key lies in selecting pieces made from inherently weather-resistant materials.
For true year-round resilience, look for furniture crafted from powder-coated aluminum, stainless steel, teak, acacia, or high-density polyethylene (HDPE) wicker. These materials resist moisture, rust, and UV damage. Cushions should have quick-dry foam and outdoor-rated, waterproof fabric.
However, "weather-resistant" does not mean "maintenance-free." Even the best furniture benefits from protective covers during harsh winter storms or prolonged freezing rain. Regular cleaning to prevent mold and mildew buildup is also crucial. Cheaper furniture made from materials like untreated iron or low-grade plastic will likely degrade quickly when exposed to continuous moisture and freeze-thaw cycles.
Ultimately, by investing in properly rated all-weather furniture and performing basic seasonal maintenance, you can confidently leave your urban outdoor setup outside all year, enjoying its functionality and style through every season.