For these firefighters, the heat isn't a problem. It's the sub-zero temperatures that make them sweat.
"It makes you miserable after you've been out and fighting the fire for a while you're fighting to keep warm and fighting to keep dry and it makes it hard out there," says Belvidere Fire Lt. Greg Holmes.
Especially when hose water and sweat get trapped inside their uniforms.
"You're soaked inside and you're hands get cold, your fingers get cold," he says.
So that's why firemen keep a spare set of clothing on board. But it's not just cold bodies to worry about, there's frigid equipment . Lieutenant Holmes says winter months can be tricky since truck drains could freeze up, along with water gages. This makes it tough to tell how much pressure is being pumped out.
"If you're not constantly pumping water and circulating it through the pump eventually it will get parts of the pump that will start freezing up and you can't get water through the pump," Holmes says.
Which could cause a road block in saving our lives. Holmes says he hasn't personally dealt with a frozen truck, but says he hears about it happening all the time. In which that case the truck would have to return to the station to thaw out.
Also the faster the fire truck drives in the cold, the greater chance it gets of freezing due to the wind chill. Holmes also says with fires in more rural areas, trucks freeze up more often. Since those firemen are on the road a bit longer.
Also, once most fires are put out, firemen can thaw out in a rehab truck where there's lots of heat and warm gloves and socks.