Short answer: yes, but only when the furniture was actually designed for permanent outdoor use. Good urban outdoor furniture is not the same as a cheap patio set. It usually uses powder-coated aluminum, stainless steel, HDPE, teak, concrete, or weather-resistant fabrics, and it is built with drainage, UV-stable finishes, and robust joints. Those pieces can handle rain, sun, frost, and temperature swings much better than lightweight indoor-outdoor furniture.
That said, “all year round” depends on your climate. In a mild city, a well-made set may stay outside with little more than occasional cleaning. In places with heavy snow, salt, coastal air, or long wet seasons, even good furniture needs some care: covering it during extreme weather, checking fixings, cleaning off dirt and salt, and making sure water does not pool on seats or tables. Cheap mild steel, untreated softwood, and thin plastic may look fine for a season but often fail when left out continuously.
For public spaces, specify commercial-grade urban furniture rather than residential decorative pieces. It should have sealed feet, rust-resistant hardware, and finishes tested for UV and moisture. If it is used in a park, plaza, or rooftop terrace, also consider vandal resistance and drainage. With the right material and a small amount of maintenance, urban outdoor furniture can absolutely stay outside all year round; with the wrong piece, it may not last through the first bad winter.