The extreme cold has pushed Ottawa well below the rest of the world's coldest capital cities.

Mongolia's capital, Ulan Bator, is on average the coldest national capital in the world.

But Ottawa's overnight temperature of –29 C on Wednesday fell below that for Ulan Bator, which experienced an overnight low of about –26 C.

Ottawa residents brave the bone-chilling weather as the city is under an extreme cold warning from Environment Canada. 0:32

Moscow and Astana, Kazakhstan, two of the other coldest capitals according to the World Atlas, recorded Wednesday overnight lows of around 2 C and –13 C, respectively.

Some other temperatures from world capitals recorded overnight:

Helsinki 1 C

Reykjavik –4 C

Tallinn 0 C

Nuuk, Greenland –6 C

The overnight temperature in Novosibirsk, the unofficial capital of the Russian region of Siberia, reached a low of –14.

With wind chills making it feel like –36 in Ottawa, the public health office issued a frostbite warning that remained in effect Thursday.