Hi Encouraged,
Sometimes it's the oxidization of the hair. It loses color over time due to exposure to sunlight and washing. It's also true for real growing hair--that's how we get the term 'beach boy blonde.' And sometimes it's just the effect of different types of light. But direct sunlight can be the harshest light. Most likely it's the effect of the direct sunlight. Back 2 Natural is a great product for returning color to the hair. With summer coming up and people are outside more it's a good product to have on hand.
Regards,
John