Air Canada officials say the jets used on Yellowknife flights aren't certified to operate past -40. ((CBC))

All Air Canada Jazz flights in and out of Yellowknife have been cancelled since Sunday, due to the current cold spell that has kept temperatures in the minus-forties.

A spokesperson for the airline told CBC News on Tuesday that the Bombardier regional jets used on Jazz flights to and from the Northwest Territories' capital are not certified to operate at or below –40 C.

Beginning late Saturday, a cold snap sent temperatures plunging below –30 and –40 throughout much of northern Canada, including all of the Northwest Territories.

Daytime temperatures in Yellowknife reached a high of –37 on Tuesday afternoon. Forecasters expected it to dip to –43 overnight. Environment Canada is forecasting much of the same for the rest of this week.

Details of the cancelled flights were not listed on Air Canada's website on Tuesday.

In the afternoon, passengers waited in line, hoping to rebook on Canadian North or First Air flights that are scheduled to travel south on Wednesday.

"When it was cancelled on Sunday, I phoned somebody instead of standing in line and they rescheduled me for the flight on Monday," Edmonton-based traveller Mike Hing said.

"When I saw online that it was cancelled on Monday, so they rescheduled me again for today and then I came here in line today and now they're putting me on Canadian North tomorrow."

All of Air Tindi's flights were also cancelled Tuesday because of cold weather.