Our family of four (kids 14 & 12) swung in to Mauna Kea on the way back from Hawaii Volcano National Park to Kona - it was definitely worth the trip! Once you turn off Saddle Rd and make the drive to the Mauna Kea Visitor Center, the weather begins to change (it was around 5:45pm). It's like driving to Heaven, where you're driving above the cloud line! Made it in time for the Star Gazing program they have each evening. Watched the sun through their telescope, then hiked up one of the peaks to watch the sun set. We did not make it all the way to the observatories due to our kids age (altitude of 14,000+ ft., which they don't recommend for kids) but it was perfectly fine at the Visitor Center (>9,300+ ft.). We plan to go back again to stay for the stars at night (it was a bit cloudy that night and our kids were tired from hiking at the Volcanoes that day).