What does a red and green light indicate when seen together at night?

When you see a red and green light together at night, it typically indicates that a sailboat is heading straight toward you. In maritime navigation, vessels are equipped with combination lights that display specific colors to convey their orientation to other boats. The red light signifies the port (left) side of the vessel, while the green light represents the starboard (right) side.

When both lights are visible at the same time, it means that the observer is positioned directly in front of the vessel, which can be a critical situation. In essence, if you see both red and green lights together, it serves as a warning that the boat is on a collision course, and immediate action may be required to avoid an accident.

Other options, such as two boats approaching each other, do not apply here since both sides of the vessels would typically be visible, not just their navigation lights. Seeing an anchored vessel would likely mean observing a different configuration of lights, and it wouldn’t display both red and green together. Furthermore, while fishing boats might display navigation lights, the red and green lights would not specifically indicate their presence without more context regarding their motion or position.