Why do your wiper blades lift off of windshield when you are driving?

Wiper blades should not lift off the windshield while driving. If they're not securely fastened or the arm holding them is worn or weakened, wiper blades may start to lift off the windshield at highway speeds or during extreme winds. Worn-out wipers or an insufficient tension in the wiper arm's return spring will result in reduced contact between the blades and the windshield and can cause water to collect near the top of the windshield, even during relatively high speeds.