Mauna Kea summit at 13,796 feet is known for its clear air and as a result is the site of numerous observatories. Reaching the top should only be attempted in an off road vehicle. Driving on Saddle Rd is restricted by most rental car companies.
Follow the access road off Hwy 20 between Hilo and western Hawaii the Big Island to reach Onizuka Center for International Astronomy, which is about 30 miles out of Hilo. Between Waimea and Hilo, there are no gas stations or emergency phones.
Freezing temps are common at the summit even when it's toasty on the beach, so bring warm clothing. For detailed info, call Mauna Kea Support Services.
Every Saturday and Sunday a caravan of off road vehicals leaves at 2pm from Onizuka Visitor Center for a free tour to the observatories at the top.
