A weapon must be discernible by ordinary observation.(a) “Concealed weapon” means a weapon described in this section that is carried upon a person in such a manner as not to be discernible by ordinary observation.
Personally, I would carry openly in a belt holster to play it safe, with no garments covering it at all. I wouldn't want to take the risk that someone might disagree with me over what is discernible.
A thigh or drop leg holster would work well for wearing a coat. Personally, I just wear a second shirt that is extra warm and tuck it in.