One of the most common causes of vinyl siding discoloration is caused by UV rays coming from natural sunlight. Unfortunately, this is something that is unavoidable. As technology has improved, the siding on the market today holds up much better to the sunlight and does not fade as much. One way to combat color fading is to choose lighter siding colors. Darker colors tend to absorb more UV rays as well as heat, causing the color fading to be more noticeable. Other factors such as chemicals from lawn maintenance, mold, mildew, or even repainting a deck can cause the siding to be discolored. It is important to realize this and keep chemicals away from the siding when cleaning your deck, spraying chemicals on your lawn, etc.