It's -35 degrees, in Tower, Minnesota, the finish line for the Arrowhead 135. The windchill is -52.
Despite the absurd cold, some of the runners still finished the race. Some of them crossed the finish line with faces completely encased in ice. Seven runners are still on the course.
"It's not for the average person, that's for sure," Arrowhead 135 race director Ken Krueger told CNN.
Krueger said people from all over the world travel to compete in it. There wasn't even a discussion to postpone or cancel the race because of the polar temperatures.
"They know it's a tough race and honestly people want a tough race," Krueger says. "People want the bragging rights about finishing in the tough years."
Here's a look at some of the participants this morning:
More about the race: Runners start in International Falls, Minnesota, and make a 135-mile slog to the finish at the Fortune Bay Casino in Tower, Minnesota. They can either run, bike, ski or kick sled.
They're equipped with mandatory survival gear and are encouraged to self-rescue —there's only three checkpoints in the race. Krueger says only one racer has quit because of frostbite.
Today is the final day of the race; participants have until 7:00 p.m. to finish.
The ultra-marathon is grueling, and most racers do not finish. If the final seven runners still on the course finish, that'll mean 13 of 64 runners that started will finish.
None of the skiers or kick sledders finished. Of the bikers, only 39 out of 75 finished.
To track the final seven participants progress, click here.