Summers are normal to hot but are not very long. An in-state joke is that if summer comes on my day off, then I will go fishing. Winters are cold and long. F. Deep snow and frozen ground exist for 5 to 6 months or more. The winters are dangerous to the unprepared or careless person.
Transportation is limited in winter at times during very cold fronts.
Driving can be dangerous or non-existent during these fronts. Persons with skin problems, lung, or other difficulties should be sure the extreme cold could be tolerated. Your automobiles will need special added equipment, such as electric block heaters, for winter operation in Montana. Your winter wardrobe will need some additional items found only in the Northwest. Some can be expensive, like boots, coats, and really good gloves.