Heavy snowfall and plummeting temperatures shut schools and shops in the Greek capital on Monday, with many public services and businesses switching to remote working.
Traffic was halted on some central roads and on a national road connecting Athens to central Greece, as storm Barbara swept across the country, blanketing the capital.
Some metro stations close to the city's international airport were also shut and train routes to the northern city of Thessaloniki were suspended.
Authorities urged the public to avoid non-essential travel.
Fire brigade rescue crews had evacuated four people whose car was stuck in the snow in the Athens suburb of Aspropyrgos, according to state TV ERT.
The cold snap was expected to last until Tuesday, gradually affecting eastern and southern regions, including the island of Crete.
Heavy snow is rare in the Greek capital but the country has now been hit by extreme weather for a third consecutive winter. Until Monday's snow, winter in Greece has been unusually mild so far this year.