Schools usually don’t close at one specific “magic” temperature; instead, they close when the overall conditions are judged unsafe, especially when cold, snow, ice, or extreme heat affect buildings or travel.

Key temperature guidelines

  • In many colder regions (for example, parts of North America), schools commonly start considering closure when actual temperature or wind chill drops to around −20-20−20 °F (about −29-29−29 °C) or lower, because of frostbite and hypothermia risk at bus stops and walking routes.
  • In the UK, the old explicit minimum classroom temperature of 18 °C was removed from specific school regulations, but general workplace safety rules say indoor temperatures must be “reasonable,” often interpreted as at least about 16–18 °C for normal work.
  • For heat, there usually isn’t a single legal “too hot” point either; instead, guidance focuses on keeping pupils safe, hydrated, shaded, and limiting physical exertion, with closures or early finishes only in severe, sustained heatwaves.

What actually makes schools close

Schools typically look at a mix of factors rather than temperature alone:

  • Travel safety :
    • Ice or snow making roads and pavements dangerous.
    • Public transport or school buses not running reliably.
  • Building conditions :
    • Heating failures so classrooms can’t be kept to a reasonable minimum (often around 16–18 °C).
* In heatwaves, classrooms that can’t be cooled and pose overheating risks.
  • Local risk assessment :
    • Each school or district uses its own policy and risk assessment to decide whether to open, close, or move to remote learning.
* What counts as “extreme” can be different in a snowy northern region versus a place that rarely gets snow or freezing temperatures.

Why there’s no universal cutoff

There isn’t one global answer to “what temperature do schools close?” for several reasons:

  1. Climate differences
    • A temperature that’s routine in Canada or Scandinavia might trigger closures in parts of the southern US or UK because roads, buildings, and infrastructure aren’t designed for it.
  2. Policy differences
    • Some districts publish clear thresholds that mention temperatures and wind chill; others only talk about “dangerous” or “severe” conditions without a number.
  1. Public pressure and recent events
    • After particularly harsh winters or high-profile incidents, some school systems become more cautious and close at slightly higher temperatures if public concern is strong.

Practical takeaway for parents and students

  • Check your local school district or school website/app : that’s where any specific temperature or wind-chill thresholds and closure policies will be explained.
  • Pay attention to travel advisories, weather alerts, and messages from the school ; often the closure is triggered by unsafe journeys or broken heating/air conditioning, not the thermometer number by itself.

In everyday terms: schools close not at a single fixed temperature, but when the combination of cold/heat, wind, building conditions, and travel risk crosses the line from uncomfortable to genuinely unsafe.

TL;DR: Many districts start to consider closing around −20-20−20 °F wind chill in very cold climates, or when indoor temperatures can’t stay near 16–18 °C, but the actual decision depends heavily on local policy, infrastructure, and safety assessments rather than a universal number.

Information gathered from public forums or data available on the internet and portrayed here.