Portugal braces for extreme heatwave as temperatures could soar to 45°C

Portugal could be on the verge of a new and potentially severe heatwave, with temperatures forecast to exceed 40°C across large parts of the country, and possibly reach 45°C in some inland areas next week.

Weather models are increasingly converging on the formation of a powerful “heat dome” over Western Europe – raising concerns that Portugal’s second heatwave of 2026 could be even more intense and prolonged than the exceptional hot spell that struck between late May and early June.

According to forecasts, temperatures are expected to rise sharply from Wednesday, just days before the official start of summer on June 21.

The heat is forecast to peak between June 22 and June 26, with Portugal, Spain and France expected to be among the countries hardest hit.

Meteorologists say a key uncertainty remains the final position of a developing upper-level low-pressure system west of the Iberian Peninsula. Even small shifts could significantly alter temperature forecasts.

The warning comes only weeks after one of Portugal’s most significant heatwaves on record. The May-June event was the country’s third-longest heatwave since records began, lasting an average of 9.3 days, and the second most intense ever recorded. During that period, 25 maximum temperature records were broken, while the town of Mora, in Évora district, reached 40.3°C — the highest temperature ever recorded in Portugal during May.

Experts warn that several factors could amplify the upcoming heatwave. Soils remain unusually dry following the previous hot spell, reducing evaporative cooling and allowing temperatures to rise more rapidly. Longer daylight hours around the summer solstice will also increase solar heating.

Current forecasts indicate temperatures could reach between 39°C and 42°C in Évora and Beja, 38°C to 41°C in Castelo Branco, and 37°C to 40°C in Santarém. More extreme scenarios suggest parts of southern inland Iberia could approach 43°C to 45°C.

Forecasters are also warning of widespread tropical nights, with minimum temperatures remaining above 20°C across many regions. In parts of the Alentejo interior and the Guadiana Valley, temperatures may not fall below 25°C overnight.

Health experts consider these exceptionally warm nights particularly dangerous because they prevent the body from cooling and recovering, increasing the risk of heat-related illness during prolonged periods of extreme temperatures.

Remember the advice: stay out of the sun when it is at its most intense (11am to 5pm); drink lots of water, take things ‘slowly’, and make sure animals are kept as much as possible in the shade.

source material: LUSA/ Executive Digest

Natasha Donn

Journalist for the Portugal Resident.