I used to put my Xmas light on nails outside my house, but they would occasionally fall off due to wind or some other reason. Then I got the idea of using velcro strips to hang the lights to the nails. The velcro strips keeps the lights in place, as they have a small hole which is just the right size for the nail head. I would wrap the velcro strip around the light and then hang the strip on the nail through the velcro strip hole. An example of how this looks is below. Since I have started using velcro strips I haven’t had my lights come out once. More of the many uses of velcro strips can be found here: https://lifehackanddiy.com/things-i-like-velcro-strips/