In the end, for a VFR pilot, if there is any chance of running into rain in winter, it's all about the freezing level. The criteria for use of heat anti-icing on jets for departure is visible moisture (which can be rain, snow or mist/cloud) below +5C OAT. The pressure drop over the wings causes a small temperature reduction that eats into this margin, so it's actually less than +5C on top of the wings when you are flying in +5C free stream air, especially at lower speeds.
Due to the extreme danger of an icing encounter, this margin is probably not really enough for VFR and it would be a good idea to use +10C/5000 ft below freezing level as a planning minimum if there is any risk of a rain encounter on a trip.
You would apply this safety margin such that when you check the weather and there is any chance of an encounter with rain, you want to make sure the freezing level is 5000 ft above your planned minimum cruising level to give you at least that +10C safety margin for the entire route. If you can't cruise at least 5000 ft below the freezing level, you have to be sure the air will be free of any visible moisture on your route.
A brief encounter with snow is not too bad, from an accumulation risk perspective, if the temperature is well below freezing and the snow is very light, but still best to avoid it because the effect on visibility is severe in anything more than very light snow and it can change from light to not so light pretty fast and it's quite frightening. So stay away from snow.