Seventeen-year-old Rudy Hummel hasn't let bitter cold, rain or mosquitoes prevent him from sleeping outside every night for a full year.

The Minnesota youth is preparing to spend one last night in his treehouse in Hermantown, making it 365 straight nights outside. He endured 76 subzero nights in a snow cave. He'd pitch a tent while traveling. By his count, he slept outdoors in 30 different places.

The Boy Scout's experiment is partly a fundraiser for Habitat for Humanity and the Hawk Ridge Bird Observatory in Duluth.

Hummel says winter nights weren't so bad, even at 27 below. He says hot, humid summer nights were the worst.

He's invited friends over to sleep in his yard Friday night, and urges others to join them by sleeping out wherever they are.