Central Asia's Kazakhstan was hit by unusually cold weather, with temperatures in some areas dipping 30 degrees below the season's average, leading to school closures and flight delays, authorities said Monday.

Temperatures in the capital Astana reached at least minus 34 degrees Celsius (minus 29 degrees Fahrenheit) at the weekend, almost 30 degrees colder than the seasonal average of minus 5 C.

The cold has also contributed to unexpectedly high demand for the popular Ai-92 brand of petrol leading to shortages and halt of sales at local petrol stations, though it was not immediately clear what caused the surge of demand.

School in some parts of the country has been called off since last week, when the cold snap began. While over 4,000 municipal staff were put to work clearing the snow on Monday in the largest city Almaty, 1,000 kilometres (620 miles) south of Astana.

The country's national carrier Air Astana told AFP by telephone that 18 flights from major airports had been cancelled on Sunday and Monday due to the snow.

Astana is the world's second coldest capital after Mongolia's Ulaanbaatar.

The unusually cold spell followed a period of uncharacteristically warm weather across the Central Asian region at the very beginning of November, when temperatures topped 30 C in neighbouring Uzbekistan.

The November freeze also affected Russia's Urals and Siberia, with at least four people dying of exposure in recent days amid temperature of below minus 30 C, local authorities were quoted as saying by the media.

The weather anomaly hit this part of the world as temperatures in the Arctic are some 20 C higher than normal according to NASA.

UN's World Meteorological Organisation predicted earlier this month that 2016 will be the hottest year on record.

Central Asia, an ex-Soviet, landlocked Muslim majority region typically experiences continental climate extremes, leading to fears over the future of water supplies.