Snow usually begins falling starting in late October and continues until April, or sometimes even later months.
November until March. Lighter and drier snow falls during the winter months while heavier and more wet snow falls in the springtime.
Depending on where you live, winters can actually be quite mild. Overall, winters in Colorado are not bad as there are minimal super snowy days.
Colorado has a semiarid climate and gets a lot of sunny days. Constant sunny days means that snow often melts as quickly as it appears.
If you are using basic summer or all-season tires, consider switching them out for snow tires.