Your body doesn’t rely on clocks to tell time; it uses light intensity. Indoor lighting typically ranges from 100 to 500 lux, which is insufficient to signal morning to your body. In contrast, stepping outside on an overcast day exposes you to 5,000 to 10,000 lux, a significant difference that helps your body recognize the start of the day. This exposure to natural light triggers your brain to feel more awake and alert, setting the tone for a productive day.