The short answer is: it's not recommended to leave your outdoor furniture cushions outside permanently. While many are marketed as "weather-resistant," constant exposure will shorten their lifespan significantly.
True "all-weather" cushions are rare. Most are designed for temporary moisture resistance, not endless sun, rain, and temperature swings. Prolonged exposure leads to fading, mold, mildew, and degraded filling.
For best results, bring cushions indoors or into a dry storage area when not in use for extended periods, especially during heavy rain, winter, or long vacations. If daily storage is impractical, invest in a high-quality waterproof storage bench or use durable furniture covers designed for breathability.
To maximize cushion life, choose quick-dry foam fills and solution-dyed acrylic fabrics. Establish a simple routine: shake off debris, allow cushions to dry completely after rain (stand them on edge), and store them only when dry. This balance of protection and convenience will keep your outdoor space looking great for seasons to come.