Having grown up on the U.S. side in the Rockies, and having been a small plane pilot for a period of time flying over the mountains of Wyoming and Utah, I can say that the weather can change very, very quickly. I have personally experienced a raging snowstorm in the morning, and a bright sunny, warm afternoon on the same day - watching the snow melt. The higher you go, the wilder it can get. Also, most of the weather events are highly localized, on one side of a mountain pass you could be snowed in, on the other side you could be getting a tan. It makes planning for the weather that much harder. Years ago, my old flight instructor was killed when his plane went down in a sudden winter squall in the rockies of Wyoming. In my experience the weather was more unpredictable during the months of October and April.
It's unpredictable for sure at that time of year, you might get lucky, but then again, you might not.