Greece braces for 48 hours of extreme heat stress as temperatures soar above 40°C

Very high to extreme heat stress is expected today and tomorrow in many areas of Greece due to the strong heat wave that prevails in the country.

According to the latest forecast data from meteo.gr and the Athens National Observatory, heatwave conditions will persist in the country on Thursday 24 July, with the mercury rising to 40-42 °C and locally 43 °C in many areas.

On Friday 25 July, a slight further rise in temperature is expected with the mercury reaching or exceeding 44 °C locally.

High temperatures, combined with the duration of the heatwave, are contributing to the increased risk of heat stress in most of the country.

More specifically, according to the HEAT-ALARM biomechanical warning system and as indicated on relevant maps, Thursday 24 July is expected to bring very high heat stress in most parts of the country. Extreme heat stress in Thessaly, the northern mainland and the East Aegean islands.

On Friday 25 July, very high to extreme heat stress is expected in most continental areas, the East Aegean islands and the Dodecanese.

The 'most critical period' for wildfire conditions

At the same time, from today, Greece is entering "the most critical period of deterioration of pyrometeorological conditions" in almost all of the country, according to the FLAME pyrometeorological team of the METEO Unit of the National Observatory of Athens.

In particular, they say "the cumulative effect of the very hot and dry conditions prevailing in our country already from Sunday 20 July 2025 has led to a significant increase in the flammability of forest fuels, making it very easy for fires to start, large heat loads to develop, fire to spread rapidly and spotting to occur".

In addition, the research team adds that the potential for fire-induced fires (self-driven fires with potentially very large heat loads) is being enhanced in continental parts of the country today and tomorrow.

"From today until Saturday 26 July 2025, north/northeast (N/NE) winds are expected to strengthen in the eastern mainland and the Aegean Sea, which will lead to a significant strengthening of the potential for wind-driven fires (especially on Friday 25 and Saturday 26 July 2025).

The above leads to a significant and potentially dangerous escalation of fire weather risk, so the difficulty of controlling any incidents that may occur will be very high and locally extreme," the FLAME team underlines.