If you've never driven up to the observatories on the top of Hawaii's Mount Mauna Kea, I suggest you do so. The 4,200 meter (13,800 feet) high summit of Mauna Kea houses the world's largest observatory for optical, infrared, and submillimeter astronomy.
If you do decide to make the drive, I have two pieces of advice for you. First, even if you are wearing shorts and t-shirts because the weather at the beach is so warm, once you reach the summit at nearly 14,000 feet, it is a hell of a lot colder. I'm not saying you need to take a coat on your Hawaiian vacation... actually that is what I'm saying. Second, make sure you have a full tank of gas before starting your drive. I was making the trip with my assistant in our rental Jeep Wrangler. I had nearly 3/4 of a tank of gas when we started the journey so I was not at all worried. By the time we reached the summit, the tank was nearly empty. I wasn't sure if AAA works on island mountain tops and I didn't want to find out. Luckily, there was a mountain to come down, so gravity was on my side. Once I got the car going a few miles an hour, I killed the engine and put it in neutral. Then I just coasted down the mountain with my foot on the brake. When I finally rolled into a gas station, the jeep was on fumes. Was it worth risk? Of course! But next time, I'll fill up first.
If you do decide to make the drive, I have two pieces of advice for you. First, even if you are wearing shorts and t-shirts because the weather at the beach is so warm, once you reach the summit at nearly 14,000 feet, it is a hell of a lot colder. I'm not saying you need to take a coat on your Hawaiian vacation... actually that is what I'm saying. Second, make sure you have a full tank of gas before starting your drive. I was making the trip with my assistant in our rental Jeep Wrangler. I had nearly 3/4 of a tank of gas when we started the journey so I was not at all worried. By the time we reached the summit, the tank was nearly empty. I wasn't sure if AAA works on island mountain tops and I didn't want to find out. Luckily, there was a mountain to come down, so gravity was on my side. Once I got the car going a few miles an hour, I killed the engine and put it in neutral. Then I just coasted down the mountain with my foot on the brake. When I finally rolled into a gas station, the jeep was on fumes. Was it worth risk? Of course! But next time, I'll fill up first.