The mild spell, which is more typical of the October-November period, began in December and has continued into January, with the average temperature staying above zero degrees Celsius.
"This is a unique phenomenon for the coldest month of the year," Alexei Lyakhov, the head of the hydro-meteorological bureau for Moscow and the Moscow Region said. "We have never registered such temperatures."
He said the average temperature for January 1 was minus 8.2C (17.2F), and minus 9C (15.8F) for January 14.
Last year, conversely, most of Russia was gripped by bitter cold as temperatures plummeted to minus 34C (minus 29.2F) on the night of January 19-20, beating the minus 32C (minus 25.6F) record registered for the same day in 1927.