At least two dozen people have reportedly died of exposure nationwide and Russians used a record amount of electricity to keep warm.
Temperatures dropped to minus-30 Celsius (minus-22 Fahrenheit) overnight, Moscow's First Deputy Mayor Pyotr Aksyonov said in televised comments, and could go ever lower.
The ITAR-Tass news agency said the mercury could plunge to between minus-30 Celsius (minus-22 Fahrenheit) and minus-33 Celsius (minus-27 Fahrenheit) by dawn.
Commuters were urged to use public transport rather than cars, and many schools cancelled classes, it said.
ITAR-Tass added that conditions might relent slightly by midday on Friday.
Two people died of hypothermia in a 24-hour period in the capital, bringing the death toll this winter to 109, the Interfax news agency reported. Twelve people died of exposure in the Novgorod region, northwest of Moscow, Interfax said.
In the Volgograd region, 550 miles southeast of Moscow and less accustomed to such cold, 10 people died of exposure and schools were shut, ITAR-Tass reported.
Over the previous day, electricity consumption nationwide hit 146,000 megawatts - a record high since the Soviet collapse 15 years ago, the head of national electricity monopoly RAO Unified Energy Systems, Anatoly Chubais, said in televised comments.
Electricity consumption in Moscow, where a construction boom is in full swing and the grey streets of the Soviet era have turned into glitzy thoroughfares festooned with bright lights, reached a record of more than 15,300 megawatts, RAO UES said in a statement.Last Mod: 20 Eylül 2018, 18:16