Intense cold weather sweeping the country has led to flight delays or cancellations at most of Canada’s major airports.

Air Canada says in a notice on its website that extreme cold at Toronto and Montreal airports is causing delays, and that customers can rebook at no cost.

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WestJet has similar advisories that include airports in Halifax, Moncton and Quebec City, as well as south of the border in Atlanta, Houston and New York City.

From New Brunswick through to Alberta, residents have been hunkered down to wait out a bone-chilling cold snap, such as parts of the Prairies expected to reach lows of -55 C with the wind chill.

Environment Canada says Ontario is bracing for a big freeze this morning, with wind chill temperatures in Toronto and Ottawa expected to range from -30 C to -40 C.

A severe winter storm has been causing widespread disruption across the United States, forcing the cancellation of thousands of flights, including some destined for Canada.