Avalanches and sudden storms scare many people away. Mount McKinley is one the coldest peaks on the planet, and most dangerous in the U.S., with temps dropping to -75 degrees in the winter. This is the tallest summit in North America. The 20,320-foot-tall mountain is just one of the national park’s amazing features. The best time to attempt to climb it is in May and June. Most people choose the West Buttress route. Denali is about 170 miles from Fairbanks and about 130 miles from Anchorage.