Second, the vertical scale is about five times as great. The top of the layer is nearly 2 Km above sea level, which makes the clouds thick enough to deliver considerable precipitation. Hilo averages over three meters of rain a year, most of it from late afternoon till dawn. At that time, the heat of the day has diminished, and no longer counteracts condensation as the wet air mass flows upslope between the volcanos. A strong temperature inversion defines the top of the layer.
Clouds above are extremely rare.
They occur for the most part only when there is a weather system in the area. Yet for the rest of my visit, the night sky at the Visitor Center remained clear, dark, and dry. I saw no light domes from Mauna Kea. My friends' elderly Toyota subcompact slowed to nearly a crawl on the seventeen-percent grades of the last few miles before the Visitor Center, but we finally made it. The first task was a photo session.