Was planning on painting my car today and was told that the humidity would fog up a paint job, but will it have any bad effect on primer? thanks.

Yes it can. It will make it blush, that's the term for what happens to the primer.

2¢

Enrique

Im not worried about the look of the primer... it will be painted over.... once sanded will the primer make the top coat look bad if I paint it when its humid?