Effective Date: February 28, 2011
Responsibility: Director of Education
Cooler seasons present an increased risk of severe weather, in the form of cold weather and wind chill factors. It is paramount that children come to school dressed appropriately for the weather. However, the safety of students is the most important consideration when keeping students in at recess during severe cold weather. This guideline is intended to assist Principals in making decisions about holding outdoor recess and outdoor playtime at lunch or ‘nutrition break,’ allowing school entry, or taking other precautionary measures on extremely cold days. Wind chill is the critical factor when making a decision.
2.0 Understanding Wind Chill Factor
Wind chill factor is a measure of the combined chilling effect of wind and temperature. The advantage of wind chill factor over other measured methods is that it represents a real rate of cooling. For example, the combination of a specific temperature and wind speed can be related to how fast exposed flesh will freeze. Exposed flesh will freeze at 1625 square watts per metre. A wind chill factor of 1500 would be considered too cold for outside play.
The following combinations of wind speed and temperature would constitute a wind chill factor of 1500.
- 50 km/h - 5° C
- 25 km/h - 10° C
- 16 km/h - 15° C
When the wind chill factor is - 20° C or colder, as reported by Environment Canada, principals must give consideration to reducing the amount of time students will be exposed. Consideration of other factors before sending children outside must include:
- condition of the playground (ice, snow etc.)
- location of the school (perhaps the building or trees block the wind on the playground
- age of the students
- the adequacy of student clothing
Information pertaining to weather conditions can be obtained from Environment Canada Weather Information at http://weatheroffice.ec.gc.ca/index.html. Observed wind chill factors are published at this site, by Environment Canada. Appendix 1 will assist Principals in determining the severity of a given wind chill factor.