Following days of heavy rain in Attica and elsewhere, snowfall is expected in several parts of the country from Monday night, according to the National Meteorological Service (EMY).
Snow is forecast for mountainous parts in the country's north and western Macedonia, EMY said.
The temperature in those areas is expected to drop by between 8 and 10 degrees Celsius.
The cold snap is expected to spread to other areas, including mountainous parts of Attica late on Tuesday or early Wednesday.
Elsewhere in the country — the Ionian, Peloponnese, northern and eastern Aegean, Crete and the Dodecanese islands — there will be rain and storms while winds will reach gale force of between 8 and 9 on the Beaufort scale.