Find and purchase a roll of duct tape that matches your vinyl hot tub cover's color.
Remove the cover from the hot tub and stretch it out in your backyard. Allow it time to dry completely before attempting to tape it back together. Wait for both sides to dry before continuing.
Use the tape measure to measure out how long your duct tape pieces should be.
Cut the tape with the scissors, cutting at least two strips to cover each side.
Press the pieces of tape along the tear, adhering the two pieces of the cover together. Push down on the tape and run your hand along it, ensuring it adheres well and no air is trapped between the tape and the cover.