A tan can fade slightly overnight, but it's not a drastic change. The outer layer of skin constantly sheds, and as these cells are replaced, the tan gradually fades. This process takes an average of 7–10 days for a tan to start fading and up to 30 days for it to completely disappear.
While some people might notice a subtle difference in their tan overnight, especially after a long day in the sun, it's not likely to fade dramatically in just one night.
Factors like skin type, how much sun exposure you've had, and your natural skin tone can all influence how quickly your tan fades.
