How high can clouds go?

 High clouds have base heights of 3,000 to 7,600 meters (10,000 to 25,000 ft) in polar regions, 5,000 to 12,200 meters (16,500 to 40,000 ft) in temperate regions, and 6,100 to 18,300 meters (20,000 to 60,000 ft) in the tropical region.