
bookrat |

Link to the rule?
Edit: Found it.
Snow has the same effect on ranged attack as rain. Rain as the same effect on ranged attacks as severe wind. Severe wind causes a -4 penalty on ranged attacks.
This shouldn't need to be said, but this is for only when it is actively snowing. Not when there is just snow on the ground.

bookrat |

Storm Hunter trait:
Benefit: When fighting in windy weather, you treat the wind category as one level lower for the purposes of determining penalties on ranged attacks made with normal weapons.

bookrat |

5th level Druid spell (get it in a scroll?) Calm Weather
Or 4th level Control Weather spell.

bookrat |

True Strike spell.
Doesn't remove the penalty, but increases your attack enough so it doesn't matter. :)

bookrat |

right, but is there any way to get rid of that visibility impairment?
You didn't ask that, but here you go:
A goz mask allows you to see through fog, smoke, and other obscuring vapors as if they did not exist (this ability functions underwater as well, allowing the wearer to see through thick silt and other aquatic precipitates).
Edit: It doesn't explicitly state it, but it should work for rain and snow as well, since it can see through thick silt.

bookrat |

You could also design your own spell to make a level 1 or 2 ranger spell to shoot in rough weather conditions.