Most people associate snow days with, well, snow. But some of the most dangerous winter days happen when it's bitterly cold—even if the skies are clear and roads are dry. Extreme cold presents serious health risks, especially for children waiting at bus stops, and schools have developed policies to protect students from these conditions.
Understanding Wind Chill
When schools talk about "cold closures," they're almost always referring to wind chill, not the actual air temperature. Wind chill measures how cold it feels on exposed skin when you factor in both temperature and wind speed.
This matters because wind dramatically increases heat loss from your body. On a calm day at 0°F, you're cold but relatively safe. Add a 20 mph wind, and the wind chill drops to -22°F—cold enough to cause frostbite on exposed skin in about 30 minutes.
Why Wind Chill Matters for Schools: A child waiting at a bus stop for 10-15 minutes is exposed to wind in a way that makes wind chill more relevant than actual temperature. Schools focus on wind chill because it better predicts the actual risk to students.
Common Temperature Thresholds
Wind chill policies vary by region and even by individual district, but here are typical thresholds:
| Wind Chill | Typical Action | Frostbite Risk |
|---|---|---|
| 0°F to -10°F | Outdoor recess may be cancelled | 30+ minutes |
| -10°F to -20°F | Recess cancelled; some delays possible | 15-30 minutes |
| -20°F to -30°F | Delays likely; closure possible | 10-15 minutes |
| -30°F to -40°F | Closure very likely | 5-10 minutes |
| Below -40°F | Almost certain closure | Under 5 minutes |
Most districts in northern states use somewhere between -25°F and -35°F wind chill as their closure threshold, though this varies. Some districts publish their specific thresholds; others make case-by-case decisions.
Regional Variations
Just as with snow, cold tolerance varies dramatically by region:
Upper Midwest & Plains States: Schools in Minnesota, Wisconsin, the Dakotas, and similar areas are accustomed to extreme cold. They typically don't close until wind chills reach -30°F to -40°F. These districts are well-prepared with heated bus garages, strict idling policies to keep buses warm, and students who own proper winter gear.
Northeast: Cold closures are less common because temperatures rarely get as extreme. When they do happen, thresholds are often around -20°F to -25°F wind chill.
Midwest: Varies widely. A district in northern Ohio might close at -20°F wind chill, while one in southern Illinois might close at -15°F.
South: Cold closures for temperature alone are rare, but when they happen, thresholds are much warmer. Some Southern districts have closed when temperatures drop to single digits (above zero) if the infrastructure isn't prepared.
Why Cold Closures Happen
Schools close for extreme cold to protect students in several ways:
Bus Stop Safety: The primary concern. Children waiting outside for buses, sometimes for 10-20 minutes, are vulnerable to frostbite and hypothermia in extreme cold. Young children especially may not recognize the signs of frostbite.
Bus Reliability: School buses can have mechanical issues in extreme cold. Diesel fuel can gel, batteries can fail, and brake lines can freeze. A bus breaking down with children aboard in -40°F wind chill is a serious emergency.
Building Issues: Older school buildings may struggle to maintain safe temperatures. Heating systems running at maximum capacity can sometimes fail.
Walking Students: Students who walk to school face significant exposure during extreme cold, and schools can't always guarantee they'll dress appropriately.
What Counts as "Exposed Skin"?
Frostbite risk times assume exposed skin—typically faces. Proper winter clothing (hats, gloves, scarves, winter coats) dramatically extends the time someone can safely spend outside. However, schools can't guarantee all students have adequate gear, so they base decisions on reasonable worst-case scenarios.
Practical Tip: If your district doesn't close but conditions are extremely cold, make sure your child is properly dressed with face covered, and consider driving them to school rather than having them wait at a bus stop.
Cold Days vs. Snow Days
There's an important difference in how these days work. Snow day timing depends on conditions possibly improving—the storm ending, plows clearing roads. Cold days are more predictable. When a polar vortex is coming, forecasters can often predict dangerous wind chills days in advance, allowing districts to announce closures the night before.
Cold days also tend to be regional—when an Arctic blast hits, entire states may close schools simultaneously, unlike snow events which can be very localized.
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