Yes, regional differences are important but there are many conditions to consider on a day to day basis. Many, many, many years ago when I was coordinator of the Child Development Laboratories at Iowa State University, we did not have a specific and descriptive written policy but we told parents there would be some outdoor time most days. An amusing situation occurred when a head teacher newly transplanted from California to Iowa wrote in a letter to parents that children would play outdoors any day the temperature was above 50 degrees F.! I had an overdue chat with her about Iowa winters. Yes, temperature is important but so is wind chill factor, precipitation, activities planned for outdoors, playground facilities and conditions, clothing of the children (and teachers!). Others can probably name many other conditions to consider in making the outdoor decisions. The best answer a college student ever gave in my class was, "That all depends...…………." "Yes!" I said. "Now tell me what you'd consider in making that decision."As a head teacher during Iowa winters, I would frequently tell parents to bring their children dressed to be outdoors and we would then have them dressed to go out into the weather for the trip home. If we went outdoors first, we could quickly judge if we'd made the right decision to go out and then decide how long to stay outdoors. Teachers would handle the undressing routine for indoor activities and the dressing again for going home. That way we had one dressing and undressing routine for parents and one for teachers. There are so many worthwhile outdoor learning experiences! Yes, please PLAN for outdoor learning and not consider outdoor time just time to "turn children loose" to "free them" from indoors where "real learning" occurs.
Clothing suitable for outdoor play is needed every day, even in winter. We play outside every day unless the weather is severe, it is raining too hard, or it is below 10 degrees. Outdoor play is very important. Please be sure to dress your child properly for the weather (boots, snow pants, mittens, hats, etc.).We also have extra snowsuits, gloves, hats, etc... for children that need it.
That chart was amazingly helpful. As a person from LA and works with educators this question has come up often. I think below 60 is too cold :) but I know on the East Coast that would mean you would never go outside, so this is a good chart. People want to know what can hurt children, not personal feelings on if it's cold or not, I know that I'm overly sensitive about that and my husband from northern Wisconsin will walk around in shorts at 30 degrees.
Keeping children safe and comfortable in the winter is important to encourage play and learning. Determining how cold is too cold has more to do with the wind and weather gear that the children and teachers wear than just a temperature gauge. If children and adults are wearing several layers, water- and windproof outerwear, warm wool socks, warm hats with earflaps, insulated boots and water- and windproof mittens, then they should be safe and comfortable in most temperatures. When the wind chill starts to dip below zero, make sure that children have additional warm gear like neck gaiters or scarves that can help cover their noses and mouths. During this weather, the ice becomes crunchy and walking in the deeper snow becomes hard work, so it is also important to be sure children don't get overheated. Observation and communication with children outdoors is key in figuring out if they may need to shed a layer or two or add another layer. For example, even at days that are 20 below zero, if we are building a quinzhee or snow fort, and shoveling piles of snow, playing tag, or hiking up a sledding hill repeatedly, it is possible that children may need to shed a heavy coat and wear just their under layers that usually comprise a thermal layer, a shirt, and a sweater or jacket liner."My program is in Minnesota and we do not have a temperature cut off, but are very careful to make sure that children are prepared. It does involve lots of extras and having a washer and dryer. We strive for 45 minutes to 1 hour outside during our 3 hour day, year-round.