Wow. I just used them in like 40f and they've been fine. I did blow a foam but the tire was pretty worn and it was going to be my last pack with them anyway. I found it funny as I've blown brand new hoonsJust be careful with Choons in the cold weather - if that's an issue where you live. Here in Chicagoland its been consistently in the 30's. During our last meetup, someone had choons on their Infraction and 30 seconds into running the plastic wheels exploded. If you live in a cold climate, stock up on the choons and save them for warmer months.