Portugal's national weather service, the Instituto Português do Mar e da Atmosfera (IPMA), has issued yellow warnings for most mainland districts as a prolonged heatwave is expected to push temperatures above 40°C this week. The warning, which begins on Monday in central and southern inland areas, will expand to cover the entire mainland by Wednesday.
The heatwave is driven by an anticyclone positioned north-northwest of the Azores archipelago, pulling a very hot and dry air mass over the Iberian Peninsula. Average temperatures are forecast to run 3°C to 7°C above normal, with the central region and Alentejo seeing increases of 5°C to 7°C.
Extreme Heat and Tropical Nights
From Wednesday, the Alentejo districts will see daytime highs exceed 40°C, with inland areas of Alentejo expected to remain above that threshold from 1 to 7 July. By the end of the week, the Tagus valley and parts of Alentejo could reach 43°C. Unlike a late-May hot spell, the coast will also be affected, with highs between 35°C and 38°C. The IPMA notes that the afternoon sea breeze will be weak, allowing unusually high temperatures in coastal locations where they are uncommon.
Compounding the heat, tropical nights—where minimum temperatures stay above 20°C—are expected from Tuesday in inland areas and from Thursday in other regions. Early in the week, overnight lows will range from 12°C to 17°C, but they will rise significantly as the week progresses.
The IPMA has issued yellow warnings for the districts of Guarda, Castelo Branco, Portalegre, Évora, and Beja from Monday. On Tuesday, Bragança and Vila Real will be added, and by Wednesday, all remaining mainland districts will be under warning. Given the long duration of the hot spell, the agency warns that it is highly likely the warning level will be raised in several districts in the coming days.
This heatwave comes amid broader concerns about heat stress across Europe. A recent study by the European Trade Union Institute (ETUI) warned that heat stress threatens 130 million workers across Europe, highlighting the need for better workplace protections. In southern France, a toddler died after being left in an unlocked car during a similar heatwave, underscoring the dangers of extreme temperatures.
The IPMA advises residents to stay hydrated, avoid direct sun during peak hours, and check on vulnerable individuals. The situation will be closely monitored, with updates expected as the week progresses.
