A wind chill warning continued Tuesday for London and surrounding counties, closing all elementary schools in the city as well as colleges and universities.

All schools and facilities within the Thames Valley District School Board were closed, as well as the London District Catholic School Board and numerous privately-run schools.

Laura Elliott, director of education with the TVDSB, says "Student safety is paramount, and all the decisions we make and all the factors that come into play really put student safety at the heart of all of the decisions."

The public board is among the largest in the province, with many schools in rural areas and long walks for students to get there, and the Catholic board faces similar challenges.

"When you're looking at the exposure to very, very cold temperatures and weather, that is a consideration. When you're asking students to be out for a long period of time, if they have a long walk to school," Elliott says.

School buses in London, Middlesex, Elgin and Oxford were also cancelled for a second straight day.

Maureen Cosyn Heath, general manager with the School Transportation System, says "If there was a mechanical failure in this kind of temperature, the ability to get another change-off bus out there really puts the kids at risk if they're having to wait for a prolonged period of time before we can get a replacement vehicle out. So, those are all the kinds of things that we factor in when we make our decision in the wee hours of the morning."

Western University, Fanshawe College and Westervelt College also cancelled classes on Tuesday.

London set a new record low of -26 C on Tuesday, shattering the January 7, 1942 record low of -21.7 C, though it felt more like -41 with the wind chill.

Environment Canada is calling for extreme wind chills from -30 C to -40 C through Tuesday night and extreme caution is advised for people heading outdoors as exposed skin may freeze in less than five minutes.

To help prevent freezing of pipes in buildings, Environment Canada suggests turning on the lowest tap in the house and letting it run as a pencil-thin stream or fast drip while keeping indoor temperatures a little warmer at night.

The wind chills are expected to improve slowly on Wednesday as temperatures rise slowly and winds finally begin to ease.