Greece is expected to experience a cold spell of weather, as a powerful atmospheric pattern known as an “Omega Block” is set to drive Arctic air deep into Central and Southeastern Europe.

Temperatures will drop up to 15 degrees Celsius below seasonal norms, raising serious concerns for the 2026 growing season, according to an analysis by the international meteorological network Severe Weather Europe.

From mid-week through May Day, cooler air masses moving into the Balkans will push temperatures below seasonal averages across the country.

The most pronounced impacts are expected in northern Greece, where isolated light frosts are possible in mountainous and semi-mountainous areas. Rain and thunderstorms are forecast primarily over mainland regions, with brief snowfall possible in the mountains of Macedonia. Temperatures elsewhere in the country will drop, though without reaching extreme levels.

The phenomenon takes its name from the shape the jet stream forms in the upper atmosphere, resembling the Greek letter omega. In this configuration, a strong high-pressure system flanked by two low-pressure systems acts as a barrier, forcing cold polar air southward and trapping it over affected regions for several days.

Meteorologists warn the primary threat is to agriculture. Overnight and early-morning frost could prove devastating to crops already in bloom and to fruit trees across much of Central Europe and the Balkans. Snowfall is forecast not only at altitude but also at lower elevations in Central Europe, while strong northerly winds will significantly amplify the wind chill effect.

Meteorologists cautioned that late cold spells of this kind are becoming increasingly damaging as a result of climate change. Milder winters are causing vegetation to emerge earlier in the season, leaving plants more exposed when frost arrives in April or May, with the potential to cause total crop losses and drive up food prices.