Minnesota Statute 169.71 subdivision 3 states, "No person shall drive any motor vehicle with the windshield or front side windows covered with steam or frost to such an extent as to prevent proper vision."
Start early; taking a few minutes to warm the vehicle so frost, ice and snow can be easily removed. Do not be tempted to drive off before the job is completed. Driving is about SEEING; a little circle cleared on the windshield, in front of the driver, is insufficient, dangerous and illegal.
It is a good Idea to remove the snow off the entire vehicle so it does not engulf you, in a cloud, when you pick up speed. Clearing all the snow will prevent it from coming in through the vents, also. Finally, do not forget to give your front and rear lights some care, as well, so others can see you, your brake lights and your signals.
When stopped for this violation you will likely need to remain until you have cleared off your vehicle¹s window completely.