Temperatures across Greece are set to climb sharply from Friday through Sunday, reaching as high as 40 degrees Celsius (104°F) in some areas, before a significant weather shift brings storms and a sharp temperature drop next week, meteorologist Klearchos Marousakis of Open TV said.
Sunny conditions will dominate most of the country, with clouds developing over central and northern mainland areas and the mountains of the Peloponnese by afternoon.
Localized showers or thunderstorms are expected primarily in western and central Macedonia and the mountains of Thessaly.
Northerly winds in the Aegean will reach 6 to 7 on the Beaufort scale, with gusts locally up to 8, while winds in the Ionian Sea will remain weaker.
Mainland temperatures will range between 35 and 37 degrees Celsius, reaching 37 to 38 degrees in western regions.
Aegean island temperatures will peak between 30 and 34 degrees, with the eastern and southeastern Aegean seeing highs of 36 to 37 degrees locally.
Athens will see largely clear skies with moderate northerly winds, reaching up to 36 degrees in the city center, while Thessaloniki will remain sunny through midday before clouds and possible storms develop near the Thermaic Gulf.
Friday, Saturday and Sunday are expected to be the hottest days, with highs of 39 to 41 degrees Celsius forecast in parts of western Thessaly and western Macedonia, particularly inland areas.
The heat wave is expected to be short-lived. Starting early next week, cooler air masses from central Europe will move into Greece, dropping temperatures by as much as 10 to 12 degrees from Tuesday onward, accompanied by increased instability, thunderstorms and localized hail, mainly across central and northern mainland Greece and inland Peloponnese.