Don't worry about cloudy skies, because the Solar Floodlight works for approximately 2 weeks without ANY sunlight (at an average of eight 30-second light intervals each night)! A built-in motion and heat sensor turns the light on for people, but not for swaying tree branches. You can adjust the sensitivity of the sensor to pick up a full 90° horizontally, at a distance of up to 30 feet. Set the darkness level to keep the light from coming on too early in the evening or too late at night. Choose either a 30- or 60-second duration for the light to remain on after the last motion detected. A 14-foot cable between the solar panel and the light lets you place the security light where you need it, while allowing the solar panel to be installed facing the sun (south for homes in the Northern Hemisphere).