Wide tires + rain + daily driver = what traction
Not an A body but my 1972 Coronet is wearing BF Goodrich Radial T/A's in 255/60 all around and that thing is fine in the rain and snow. Honestly it's amazing how well that car handles in the snow. I believe wider is better for traction, but as others said, tread design and compound is also very important.
Edit: actually that might be 245/60, I don't remember off the top of my head.