Saharan Air Mass Triggers Heat Alerts Across Portugal From Friday

Tourists still pouring into Portugal’s beaches and newcomers busy unpacking in the cities should brace for a sweltering turn: meteorologists warn that the hottest spell of the summer so far will grip parts of the country from Friday onward, with yellow alerts already issued for several districts and the prospect of the warning level being raised if the mercury keeps climbing.

What’s happening and where?

Friday morning, the Instituto Português do Mar e da Atmosfera signalled that a pocket of exceptionally warm, dry air moving north from the Sahara will park over the Iberian Peninsula. By mid-afternoon, Beja, Évora, Faro, Lisboa, Portalegre, Santarém and Setúbal are all forecast to top 34 °C, and interior valleys could flirt with 40 °C as early as Saturday. The notice was originally flagged for six districts but expanded overnight as forecast models converged. Coastal spots such as Cascais and Lagos will feel milder sea breezes, yet the agency still expects so-called noites tropicais—minimums stuck around 22-23 °C—even along the Atlantic shore.

Why temperatures are spiking again

Climatologists point to a familiar culprit: the Azores High inching eastward and blocking cooler fronts from the North Atlantic. That stationary high-pressure dome funnels heat from North Africa, dries out the lower atmosphere and sharpens inland temperature gradients. The same pattern shattered a June record of 46.6 °C in Mora and underpinned a string of record-breaking summers across the Iberian Peninsula over the past decade. While this week’s peak is unlikely to threaten the all-time Portuguese mark of 47.4 °C set in 2003, the persistence of the ridge means daytime extremes could endure into early August.

What the alerts actually mean

IPMA’s yellow tier serves as an early heads-up rather than a confirmation of danger, but it still implies “risk for certain activities.” The threshold is district-specific: Lisbon enters yellow when forecasts exceed 33 °C, while Alentejo districts need 35 °C. Should observed temperatures overshoot by another 3-4 degrees, the alert shifts to orange, triggering tighter civil-protection protocols, including extra ambulance crews and more patrols in wildfire-prone corridors. Foreign residents unfamiliar with the color code should monitor IPMA’s map or install the free MeteoPT app, which sends push notifications whenever a status changes.

Practical tips for newcomers

The Direção-Geral da Saúde has repeated advice many long-term residents now follow instinctively: drink water even when not thirsty, schedule errands before 11:00 or after 19:00, wear loose cotton layers, apply SPF 30 + sunscreen frequently and never leave pets or children in parked cars. Locals also close shutters during the day, a trick that can knock two or three degrees off indoor highs. Grocery stores and shopping centres—equipped with mandatory HVAC—double as low-key cooling centres; many municipal libraries do the same. If your rental lacks air-conditioning, landlords must legally ensure “minimum habitability” but the statute sets no upper cooling limit, so purchase of a stand-alone fan may fall on the tenant.

Fire risk and public services

Hot, gusty afternoons dramatically raise the wildfire danger index, particularly across the interior Alentejo and Algarve hills where brush dried out after a dry spring. National civil-protection officials already classify 30 municipalities from Bragança down to Faro at “very high” or “extreme” risk. During such periods, it is illegal to light barbecues in forested areas, operate chain saws without spark arresters, or burn garden waste without prior municipal approval. Train and long-distance bus schedules remain unchanged, but heat-related speed restrictions on some main roads are possible; a similar cap was enforced on the A6 during last year’s July scorcher. Hospitals in Lisbon and Évora have prepared overflow cooling bays, though no spike in heatstroke admissions was reported through Wednesday night.

Looking at the bigger climate pattern

This episode slots into a broader trajectory: seven of the last ten summers in mainland Portugal ranked among the hottest on record, and 2024 closed as the planet’s warmest year globally. Scientists from the University of Porto say the Iberian Peninsula now witnesses twice as many heat-wave days as it did in the early 2000s, with the interior seeing the sharpest increase. In practical terms, expats accustomed to cooler northern climates will need to normalise midsummer highs above 35 °C and plan housing, schooling and leisure around that new reality. For now, the immediate takeaway is simpler: keep a bottle of water handy, check the IPMA map before heading inland, and remember that Portuguese summers can sizzle long after the beach crowds thin out.