When is it necessary to use headlights during the day?

Using headlights during the day is necessary in specific conditions, such as fog, rain, or snow, because these weather conditions can significantly reduce visibility. Headlights enhance your ability to see the road and your surroundings, while also making your vehicle more visible to other drivers. This is particularly important in inclement weather, where dark clouds or precipitation can obscure a driver's view, making it challenging to perceive other vehicles, pedestrians, or obstacles on the road.

While it's important to use headlights at any time that visibility is compromised, including in tunnels, headlights are specifically necessary in adverse weather to ensure safety. Simply relying on daylight visibility is not sufficient when external factors, like weather conditions, can create a hazardous driving environment.