A Yellow Heat Warning Blankets Every Mainland District but Faro as the Douro, Tejo and Guadiana Valleys Push Past 40 Degrees
IPMA has placed every mainland district except Faro under a yellow warning from Monday morning to Tuesday evening, with the Douro, Tejo and Guadiana valleys forecast to pass 40°C and tropical nights in the eastern Algarve. Almost the entire mainland faces maximum or very high fire danger.
Portugal begins the week under a broad heat alert. The Portuguese Institute for Sea and Atmosphere (Instituto Português do Mar e da Atmosfera, IPMA) has placed every mainland district except Faro under a yellow warning from 09:00 on Monday to 18:00 on Tuesday, as temperatures climb well above the seasonal norm across the country.
The hottest air will sit over the interior river valleys. IPMA expects maximum temperatures to reach or pass 40°C in the Douro, Tejo and Guadiana valleys on Monday, with Santarém, Beja and Évora forecast to touch 40°C on both Monday and Tuesday. Highs of 29°C to 41°C are predicted for the interior north and centre and 33°C to 41°C in the south, while the western coast stays more moderate at 23°C to 34°C and the southern coast at 26°C to 37°C.
Little relief after dark
Nights will bring only partial respite. IPMA is forecasting "tropical nights" — when the temperature never drops below 20°C — in the Sotavento (eastern Algarve) and, on some days, in the border regions and the same Douro, Tejo and Guadiana valleys that bear the brunt of the daytime heat. Minimum temperatures are expected to hold between 13°C and 22°C, keeping homes warm and making sleep difficult in the worst-affected areas.
A yellow warning is the lowest of IPMA's three-tier system, signalling a weather situation that carries risk for certain activities and for vulnerable groups rather than a widespread emergency. Health authorities routinely advise residents during such spells to drink water regularly, avoid the sun during the hottest hours, keep homes shaded and ventilated, and check on elderly neighbours and people living alone, who are most exposed to heat stress.
Fire danger at its peak
The heat carries a second, sharper risk. IPMA and the Institute for Nature Conservation and Forests rate almost the entire mainland at maximum or very high fire danger on Monday and Tuesday, as high temperatures, low humidity and dry vegetation combine. The warning lands as Portugal watches devastating wildfires burn across the border in Spain and in south-western France, where Portuguese water-bombing aircraft and crews have been deployed to help.
Civil-protection rules tighten automatically on days of extreme fire risk: farm burning and the use of machinery that can throw sparks are restricted, and access to some woodland is limited. IPMA's forecast points to slightly cooler air arriving mid-week, but for now the message from the authorities is to treat the countryside as a tinderbox and to take the heat seriously indoors as well as out.
