The brightest Christmas lights are typically the LED lights that are made with the most advanced technology. These lights can be up to 300 times brighter than traditional incandescent bulbs and can be found in various colors, including white, blue, green, and red. The brightness of these lights is measured in lumens, and the more lumens a light has, the brighter it is. So, the brightest Christmas lights you can find are the ones that have the highest number of lumens.