As far as I'm concerned it's ok for Prepared, but only if you use HDR Lighting.
On the other hand if you fly FSX and have

Here are a few shots in and around Vancouver to give you a little idea of what it looks like. Remember this is Prepar3d with HDR Lighting turned on. FSX will be better.
The Plane, The Plane!




PS - Sometimes the snowflakes actually stick to the windshield!

Of course that's only when you're going slow, and they don't last that long. Kinda like when you have snow blowing against the auto's windshield.