The Portuguese Institute for Sea and Atmosphere (IPMA) has escalated warnings to the highest level for four districts, including the capital Lisbon, as an intense heatwave grips the country. The red alert—signaling an extreme weather risk—will be in effect for Lisbon and Setúbal from midnight Thursday through Friday, while Coimbra and Leiria face the same warning on Friday and Saturday.
This episode of extreme heat, driven by an anticyclone positioned north-northwest of the Azores archipelago, is expected to last at least a week. The IPMA notes that the situation is particularly unusual for coastal regions, where the weak inland penetration of the sea breeze will contribute to high temperatures over several consecutive days, creating a rare meteorological event in some areas.
Temperatures Soar Across Mainland Portugal
Maximum temperatures across the country are forecast to exceed 35°C, with inland and southern areas seeing values above 40°C. The Alentejo region could reach 43°C at least until Monday of next week. Minimum temperatures will also remain high, staying above 20°C in much of the mainland, with some areas—including Greater Lisbon—experiencing nights where temperatures do not fall below 24 to 28°C.
On Wednesday, the districts of Castelo Branco, Portalegre, Évora, and Beja were already under an orange warning (the second-highest level, indicating moderate to high risk). This orange alert will extend to all of mainland Portugal on Friday as the heatwave intensifies.
The extreme heat is part of a broader pattern affecting southern Europe. Earlier this summer, Spain's second heatwave of summer 2026 placed nine regions under alert, with temperatures approaching 42°C. The Copernicus Climate Change Service has warned of 'extremely unusual' heatwaves across Europe with no relief in sight, highlighting the continent's growing vulnerability to prolonged heat events.
Health Risks and UV Warnings
The IPMA also warns of very high to extreme ultraviolet (UV) index values across mainland Portugal through Friday. UV index values of 10 (very high) to 11 (extreme) are expected, prompting the institute to advise against sun exposure around solar noon, which occurs at approximately 1:30 PM local time at this time of year. The IPMA recommends avoiding sun exposure between 11 AM and 4 PM, and using sunglasses with UV filters, hats, T-shirts, parasols, and sunscreen.
Health authorities across Europe are increasingly concerned about the impacts of such heatwaves. The WHO Europe chief has urged governments to treat extreme heat as a health emergency, as heat-related deaths and hospitalizations rise. In Portugal, the prolonged nature of this event—with high minimum temperatures offering little nighttime relief—poses particular risks for vulnerable populations, including the elderly and those with pre-existing health conditions.
The heatwave also raises broader questions about European preparedness. As French hospitals race to adapt to recurring heatwaves, similar challenges are emerging across the continent. The current episode in Portugal underscores the need for robust early warning systems and public health responses, especially as climate models predict more frequent and intense heat events in the coming decades.
For now, residents and visitors in the affected districts are advised to stay hydrated, limit outdoor activities during peak heat hours, and check on neighbors and relatives who may be at higher risk. The IPMA will continue to monitor conditions and update warnings as the heatwave evolves.
