The Instituto Português do Mar e da Atmosfera (IPMA) has placed mainland Portugal and both the Madeira and Azores archipelagos under a very high UV radiation alert this week, with conditions expected to persist through at least Friday, June 12. Some southern regions—particularly Évora, Beja, and Portalegre—have already recorded UV index readings of 10, classified as extreme by the institute.
Why This Matters
• Peak risk window: The alert began June 9 and covers the entire national territory through mid-week.
• Extreme readings in Alentejo: UV index 10 was measured in southern districts—threshold for maximum protective measures.
• Children at heightened risk: IPMA specifically advises keeping children out of direct sun during peak hours.
• Long-term uptick: Portugal has seen a 1.1% per decade increase in UV levels over the past 50 years, according to satellite data.
Geographic Scope and Timing
Every district across continental Portugal, as well as Madeira and the Azores, falls within the very high risk category through the end of this week. The escalation began Tuesday and coincides with a high-pressure system delivering cloudless skies and maximum daytime temperatures approaching 30°C in parts of the interior. June routinely brings the year's most intense ultraviolet exposure in the Northern Hemisphere—Lisbon's historical UV index peaks at an average of 9 during June and July—but this week's readings edge into the extreme band in multiple locations.
The IPMA scale runs from low to extreme, with 8 to 10 classified as very high and anything above 11 rated extreme. The southern Alentejo—a flat, open landscape with high reflectivity—regularly records the country's most intense UV, and the current spell underscores that pattern.
Why Levels Are So High Right Now
Four factors combine to drive this week's elevated readings:
Solar elevation: June marks the sun's highest arc across the sky in the Northern Hemisphere, shortening the distance ultraviolet rays travel through the atmosphere and reducing ozone absorption.
Clear skies and stability: A stationary anticyclone has parked over Iberia, eliminating cloud cover and allowing maximum solar radiation to reach the surface.
Reflective surfaces: Coastal sand reflects between 25% and 40% of incident UV, amplifying exposure near beaches and open terrain.
Geographic latitude: Portugal's position ensures significant year-round solar flux, with June representing the annual peak.
While ultraviolet spikes are a predictable feature of early summer, the broader trend is less benign. Satellite observations spanning nearly five decades show a statistically significant 1.1% ± 0.9% per decade increase in clear-sky UV index values across Portugal, a slow but measurable climb that raises baseline exposure with each passing year.
What This Means for Residents
The IPMA issues tiered guidance depending on the risk level in a given area.
For extreme-risk zones (currently parts of Alentejo): Avoid outdoor exposure altogether when possible, especially between 11:00 and 16:00, when solar angle and intensity peak.
For very high-risk areas (the rest of the country): Wear UV-filter sunglasses, a wide-brimmed hat, a cotton or long-sleeve shirt, and apply broad-spectrum SPF 30+ sunscreen every two hours. Use a beach umbrella or parasol and keep children indoors or fully shaded during midday hours.
For high-risk zones (none currently, but typical in spring and autumn): Sunglasses, hat, shirt, and sunscreen remain the baseline precautions.
Burns can occur in as little as 15 minutes under a UV index of 10, and cumulative exposure over years raises the risk of melanoma and other skin cancers. The Direção-Geral da Saúde recommends scheduling outdoor activities before 10:00 or after 17:00 during alert periods and emphasizes that children's skin is particularly vulnerable to long-term damage.
Historical Context and Seasonal Patterns
Very high UV alerts are not unprecedented in Portugal—similar warnings were issued in June 2020—but the regularity and intensity of these episodes appear to be edging upward in line with the long-term satellite trend. June and early July consistently deliver the year's harshest ultraviolet conditions because the Tropic of Cancer tilts closest to the sun, minimizing atmospheric filtering.
What makes this week notable is the combination of extreme southern readings and blanket coverage of the archipelagos, which are typically moderated by maritime air masses. The persistence of the anticyclone has suppressed the usual Atlantic influence, leaving even island communities exposed to continental-style UV loads.
Practical Steps and Resources
Residents can check daily UV forecasts on the IPMA website and mobile app, which publish index predictions by municipality. Pharmacies and supermarkets stock high-SPF sunscreens, though dermatologists recommend mineral-based formulas containing zinc oxide or titanium dioxide for prolonged outdoor work.
For those working outdoors—agriculture, construction, tourism—employers are legally required under occupational health standards to provide shaded rest areas and scheduled breaks during peak solar hours when UV exceeds index 8.
Parents should apply sunscreen to children 20 minutes before outdoor play, reapply after swimming, and consider UV-protective swimwear rated UPF 50+ for beach outings. Infants under six months should not be exposed to direct sun at all, according to pediatric guidelines.
Outlook and Ongoing Monitoring
The current alert window runs through Friday, but the IPMA will update forecasts daily as atmospheric conditions evolve. A trough approaching from the northwest may bring increased cloud cover by the weekend, temporarily lowering UV exposure, though models remain uncertain.
As the climate continues to shift, public health authorities expect UV management to become a year-round concern rather than a seasonal one. The steady per-decade increase documented by satellite data suggests that by mid-century, today's extreme readings may represent the new summer baseline, making education and behavioral change critical for long-term population health.
