When your camera is looking for a meter reading it views the world outside of itself as a neutral gray
That is because your camera needs a starting point to figure out what proper exposure is. Whenever you’re presented with an environment that has a lot of light or is very dark you’re most likely going to get inaccurate meter reading.
I live in Southern California and do a lot of family portraits on the beach. This is a problem I encounter frequently and, this video explains why.