Unstable weather is set to affect much of Greece over the Christmas holiday, with rain and locally strong thunderstorms forecast for both Christmas Eve and Christmas Day, according to the national weather service.

Cloud cover and rainfall are expected across most of the country, while stronger storms are forecast in western regions and parts of the northern Aegean. Snowfall is also likely at higher elevations, affecting mountainous areas in northern and central mainland Greece.

Authorities have issued an orange-level weather warning for Christmas Eve, citing intense weather systems that are expected to spread across western Greece, parts of central and northern mainland areas, and islands in the northern and eastern Aegean. Conditions are forecast to ease gradually overnight in western regions and by Christmas afternoon elsewhere.

In major urban centers, the holiday weather will be gloomy. Athens is expected to see cloudy skies and rain, with temperatures ranging from 46°F to 63°F (8°C to 17°C). Similar conditions are forecast for Thessaloniki, where temperatures will range between 46°F and 55°F (8°C to 13°C).

On Christmas Day, rain and scattered thunderstorms may persist in northern and eastern mainland regions, as well as across the northern and eastern Aegean. Western areas are expected to see intermittent rainfall, particularly during the early morning and evening hours. Crete is likely to experience variable cloud cover with occasional showers, while light snow is expected in mountainous inland areas later in the day.

Weather conditions are forecast to improve on Friday, although heavy rain may continue locally in parts of eastern central Greece before tapering off by evening. Snowfall will remain limited to higher elevations. Winds will strengthen in eastern regions, particularly over the northern Aegean, while temperatures will drop nationwide. Frost is expected in northern inland areas during the early morning and nighttime hours.

By Saturday, rainfall will be limited mainly to eastern and southern areas, with generally calmer conditions elsewhere. A clearer and more stable weather pattern is forecast for Sunday, when skies are expected to be mostly sunny with only isolated cloud cover, marking a calmer end to the holiday period.