Showers and thunderstorms are expected to hit Central and Eastern Macedonia, the islands of the Sporades and northern Evia late on Friday and on Saturday, the Hellenic National Meteorological Service (HNMS) said on Friday.
Downpours are expected to be quite strong in parts and may come with hail, while winds will also pick up to reach speeds of 7 to 8 Beaufort, especially in the north.
The islands of the Cycaldes and the northern and southern Aegean will enjoy sunny skies, though midday temperatures will remain quite high at between 36-38 degrees Celsius on Saturday.
Athens will also enjoy sunshine on Saturday and Thessaloniki is expected to see some clouds and possible showers.
Temperatures will dip to more tolerable levels across the country over the weekend and on Monday, though they are expected to start inching back up into heat wave territory from Tuesday.