Strong blue cast

Hello.
I am Spywayman from Dorset in England.
Earlier this month I was given a hand me down D80 am am still trying to get used to it.Yesterday, I went to the beach on what was a predominately overcast day. I took a few pictures and when I saw them on the computer, there were about four with a strong blue cast, as if shot through a blue filter. A few minutes later, when I had turned about 150 degrees to face south the picures are quite normal.
The White Balance is set to Auto.
If anyone has any idea about this, I would be interested to hear.

Sounds like your WB had a bit of a brain fart. The blue is typical of a very cool WB temp and perhaps something was interfering with the WB sensor in some way that convinced it to down temp the WB? Hopefully this is a one-off and you won't have any more issues with it.

I had a similar problem a couple of years ago. Shot two of my grand daughter's soccer games and it turned out the WB was set to Tungsten(incandescent) light. I shoot in RAW so it was an easy enough fix in Lightroom. After I figured out one of them, I just group copied the changes to all the others. It has taken me a long time, to learn, but I now check the WB as soon as I get the camera out now.

Thank you both. Perhaps it was a Nikon senior moment!