Why is the complexion black on cloudy days?

Um ... . You're playing me. Seriously, I haven't observed it on my body, mainly on my face. From white to black to white is not so obvious, but it is very dark and dim. I have observed it for many years. When I was in high school, my deskmate said that she didn't dare to provoke me on cloudy days, and she always felt gloomy. . .