How dynamic is it?

What kind of dynamic are you asking?

Not very. To be honest I think it's a cut feature, cause I really see no difference when it's snowing and when it's not, just the visible climate change.

i enjoy questing in an area where there is a blizzard then watching it slowly dissipate as i go about my business. its nice

Wasn't this hyped up?

I don't think so. It accumulates, changes the textures to appear white and fades away. I don't know of many games that do this, though I can't say my knowledge is extensive. I guess it depends on what you want. For example I don't think it forms snow drifts.