Well bigj I have seen Denver, Colorado go from low 70s for a high temp down to the mid teens with snow in 24 hrs. The plains east of the Rockies have the biggest temperature swings anywhere in the continental US. Exceptionally cold arctic air from Canada dropping down east of the Rockies can cause quite the roller coaster in temperature. The reverse is true too when the Chinook winds come from the Rockies Eastward to the plains. Compression of air causes the air to heat up very, very quickly at times. In one place somewhere in North Dakota or South Dakota it went from -4°F to 49°F within 2 minutes. Crazy indeed.