For weather info, go to http://www.nws.noaa.gov/and click on the map where you're going to be.
Also, there are a lot of web cams all over the net these days. I use this one for the area I go:
http://www.dayweather.com/keystone/weathertext.html

Try the Colorado Dept. of Trans. (CDOT) and see what they have for web cams on roads near or at your destination or route. You can see right now what the weather is doing.
Other than that, dress warm and in layers. Boots need to be tall, insulated, waterproof, comfortable, and plenty of grip for stumbling over snow covered obsticles. Taking care of your feetcan mean all the difference in enjoying or hating a hunt in the Rockies this time of year.

And one small reminder . . . know what you're shooting at.