Especially for kids, neck warmers (sometimes called gaiters or ski gaiters) are a practical option for cold days. Scarves can be too long and difficult to manage, and can even be dangerous if they get tangled in playground equipment or ski lifts. Yet kids need something around their necks to provide more protection from cold and wind. A neck warmer is like a cowl, or a smaller version of an infinity scarf—it's a loop of fabric (or crocheted yarn) that fits over the head and around the neck. If you have one made of a stretchy, breathable fabric, you can pull it up over your nose and mouth as needed, or put it up higher to make it into an ear-warming headband.
You can buy neck warmers in sporting goods stores but you can also make your own very easily. All you need is an old winter hat. A stretchy knitted hat works well. A slightly loose-fitting fleece hat is also a good choice. The sample neck warmer in the photos is made from a double-layered fleece hat.
Start by snipping off any pom-poms or tassels on the top of the hat. Then turn the hat inside out. Depending on how your hat was constructed, it will probably have several seams at the top. Cut these apart and you will have an opening with several points. You can leave these as is, tucking them in when you wear the neck warmer. Or you can fold them under and stitch them down. Another option is to cut them off, then make a quick hem with fabric glue or needle and thread. If your hat is knitted, you may still want to create a hem (even if the hat doesn't have these pointy ends) so that the edges of your neck warmer don't fray.
If your hat is lined with a layer of fleece, cut that open too. Pull the layers apart and you will have a longer tube of fabric, so your neck warmer can cover more of your chin, neck, and chest. Now you're ready to play in the snow!