The short answer is: it's not recommended. While outdoor cushions are designed to be weather-resistant, leaving them exposed to the elements year-round will significantly shorten their lifespan. Constant sun exposure can cause fabrics to fade and become brittle. Rain and humidity can lead to mold, mildew, and internal foam damage that is difficult to reverse. Even "all-weather" materials degrade over time with relentless exposure.
For best results, develop a simple care routine. Use protective, waterproof covers when the furniture is not in use for extended periods. During harsh weather or the off-season, store cushions in a dry, ventilated area like a garage or shed. For daily use, propping cushions on their side after a rainy day allows for thorough drying and prevents moisture buildup. This routine protects your investment, ensures comfort, and maintains the vibrant look of your outdoor living space.