You'll go from 85 degree weather near sea level to 35 degrees at the summit, all in a matter of a couple hours! The road to the top was challenging for us in our 4-cylinder rental cars. The drive can be frightening if you're afraid of heights. It's all worth it for the views at the top, though. There's also a space observatory around the 9000 feet mark. On our way back, after spending time at the peak, we stopped at the observatory and they held a stargazing session. It's one of the best places in the world to view the stars, since it's right in the heart of the Pacific Ocean and not corrupted by light pollution.