No. Reputable vinyl extruders include Titanium Dioxide (TiO2), which is an ultraviolet inhibitor, in their vinyl fence extrusions in order to combat the discoloring effects of the suns rays. A quality vinyl fence extrusion will include at least ten parts Tio2 per 100 parts.
Vinyl fences are designed to be long-lasting and resistant to fading. Even though it doesn’t fade you should still clean and maintain it regularly. This can include washing it with a mild detergent and water, and applying a vinyl fence protectant to help protect it from the elements. In general, a vinyl fence should retain its color for many years with proper maintenance.