It gets very dark at night. Even with the moon, it can be hard to see where you're going. The darkness makes the road dangerous for cars and bicycles at night, so make sure to have adequate lights when you go out.

The county uses yellow LEDs to cut down on light pollution for the astronomers. The lights are directional and produce light in a narrow band which can be more easily filtered by telescopes. [1]

At night, invasive coqui frogs blast their mating calls at 90 decibels.

[1]: http://bigislandnow.com/2012/08/28/shift-to-high-tech-streetlights-saves-dark-skies-money/