Products with the UV label are designed for outdoor use. They contain a UV stabiliser that preserves the colour, even in full sun, and they are weather-resistant.
UV resistance is tested in the lab through accelerated weathering with a xenon arc lamp according to ISO 4892-2:2013, cycle 1 (minimum 1,000 hours, up to 2,000 hours).
It is hard to guarantee an exact number of years, as UV exposure depends on orientation, weather and location. As a guideline, you can count on at least 3 years without visible colour loss outdoors. Indoors, depending on direct sunlight, the lifespan is considerably longer.