When my review sample arrived I had the perfect way to test it for outdoor use: we are in our rainy season in Central Florida and I wrapped one of my palms in the middle of the yard to test it out.The first test was using the timer feature, where this would come on for six hours, shut down for eighteen, and turn turn back on for six. That worked, but that only proves that the timer worked. What makes this impressive is it endured blazing sun on the south side of my house, then torrential rain, and continued to operate like clockwork.Not only did it prove that it could withstand the elements, but the lights were exceptionally bright at night. Not glaring bright because this is the warm model with the light having an orange tint. Still, the illumination is impressive.The battery case is totally waterproof too. It was actually on the ground the entire test. I was frankly surprised that the batteries did not cook in the hot sun and prematurely fail, but since this did not come with those batteries (you need to supply your own), it would have not been germane to these lights if they did.To be honest I do not intend to leave these out permanently. I want to use them for temporary decor for parties and seasonal events like Christmas and Halloween. Still, if they were to be used permanently I am betting they they would survive because mine took a beating during my evaluation and continued working perfectly. I would love to see a solar adapter for these lights because running them on batteries would get expensive if they were placed in a permanent location.Bottom line: these light up outside spaces and objects beautifully. A few placed strategically in a yard or on a patio can create a magical ambiance.