Your local was correct. While it can get chilly, winter in Colorado doesn’t usually get started until January. March is the heaviest snow month, and April the second. However, Colorado has very wild weather where “typical” doesn’t mean much. I have been in five foot snowstorms on Thanksgiving and Christmas. It has snowed as early as September, and as late as May.
We were blissfully ignorant and lucky to not be snowed in with a 30’ trailer that was not winter prepped.