Icing is, and will be for a long time a "gray" area. The only actual "Known" icing is from Pireps. There's prediction info etc..., but it's not always accurate, and covers vast areas. I'm not saying it's good/smart/safe to attempt flying is (0)-(-10) temps and in clouds with a single-engine, small GA plane, because it isn't. Something with more horsepower, prop-protection at a minimum, and speed, usually is more apt to handle these adverse conditions.