Kids can stay outside for hours if the temperature is on the higher end of “below freezing,” but when the wind chill plunges, you’ll want to limit outside play to 30 to 60 minutes at a time. These frequent breaks not only allow your kids to warm up on a regular basis, but they will give them an opportunity to drink a mug of cocoa or have some warm soup, which can help them stay hydrated. They can also take that time to swap out clothing that has become wet.