Windshield wipers can freeze to the windshield in the winter. Before turning on your wipers you will want to make sure they are not stuck to the windshield. If your wipers are frozen to your windshield it is recommended to turn on your car and run the defroster until you can thaw the windshield enough to move them.
If you know your car will be sitting in sub-zero temps and wet conditions, you can always lift the wipers away from the windshield. Also, be sure you use winter-specific windshield wiper fluid that is suitable for use in cold temperatures.