A large light that turned white, green, and pink.I was outside playing tennis with overcast skies and slight rain when I saw a large round light in the sky. The light started out as bright white and turned a light green, then quickly turned pink. I watched the light for about 20 seconds then turned to my friends and said, "Hey guys, look at this!" I pointed to the sky where the light no longer was. I looked all around the sky but unfortunately found nothing.