Portugal prepares for first total solar eclipse in 114 years on 12 August

A century-long wait

Portugal will witness its first total solar eclipse over mainland territory since 1912 on Wednesday, 12 August. The event is also the first total solar eclipse visible from the Iberian Peninsula since 1905. It occurs when the Moon passes between Earth and the Sun, completely blocking the solar disk. Only a narrow strip of northeast Portugal, between the villages of Rio de Onor and Guadramil in Bragança district, will experience full totality. The rest of the country will see a partial eclipse ranging from 74% to near-total coverage.

Filipe Ferreira da Silva, a professor at the Department of Physics at NOVA FCT, explained to DN that a total eclipse requires the Moon to be perfectly aligned with Earth and the Sun. Because the Moon's orbit is inclined about five degrees relative to Earth's, such alignment does not occur every month, and the projected shadow covers only a relatively narrow band of the planet.

Timing and visibility

The eclipse will begin at 18:32. Peak coverage will reach 100% in Bragança at 19:31, 98% in Porto at 19:32, 95% in Lisbon at 19:36, and 93% in Faro at 19:38. The total phenomenon will last roughly two hours, ending around 20:29, but the period of total darkness will last only about 26 seconds.

Weather outlook

The IPMA released its updated forecast on Monday. For most of mainland Portugal, skies will be clear or mostly clear during the eclipse, including the zone of totality at Parque Natural de Montesinho in Trás-os-Montes. However, the coastal strip north of Cabo da Roca may have heavily clouded or overcast skies by 19:00, which the institute described as a usual situation at this time of year. Cities potentially affected include Caldas da Rainha, Marinha Grande, and Viana do Castelo. The area between Aveiro and Póvoa de Varzim, including Ovar, Espinho, and the mouth of the Douro in Porto, will be most affected. The IPMA recommends moving inland and to higher altitude. IPMA meteorologist Jorge Pontas confirmed to Observador that models show the signal for low cloud formation along the North and Center coast.

Safety warnings

Experts have warned that looking directly at the Sun without certified filters, even during partial phases, can cause severe and irreversible eye damage. Filipe Ferreira da Silva cautioned that even 1% of the Sun's surface remaining visible delivers intense light.

Even if it is only 1%, that intensity is very high. And we are looking directly at the Sun.

Pedro Mota Machado of the Comissão Nacional do Projeto Eclipse noted that the retina has no pain receptors, meaning damage can occur without immediate sensation. The website Eclipse2026 published three indirect projection methods for those without certified glasses, including a simple pinhole projection using cardboard and a pinhole camera made from a shoebox.

Viewing spots and flights

Tickets for two of Sintra's most emblematic viewing locations, the Pátio dos Arcos at Palácio Nacional da Pena and the Farol do Cabo da Roca, have sold out. Both sites open at 17:00, with the Moon beginning to cross the solar disk at 18:39 and peak coverage of about 95% at 19:36.

Vueling announced that 11 flights will coincide with the eclipse. On two routes, Barcelona-Lisbon and Palma de Mallorca-Lisbon, passengers will be able to observe totality from altitudes between 30,000 and 36,000 feet. The airline will distribute eclipse glasses on board. The other nine flights will cross areas near the eclipse path, offering partial views weather permitting.

Scientific research

The eclipse offers researchers an opportunity to study the solar corona, whose extreme heating remains unexplained. Pedro Mota Machado said scientists can observe the chromosphere and corona around the Sun during totality. The phenomenon also produces "Baily's beads" and the "diamond ring" effect from the last bright point on the solar surface.

A separate study involving Portuguese and Spanish academic institutions will examine animal behavior during the eclipse. Paulo Cortez of the Instituto Politécnico de Bragança said audio monitoring equipment has already been installed in the Montesinho forest to track bird activity.

We expect, effectively, that with the darkening there will always be animals that have more or less activity, but likewise when the sun starts to become uncovered we will have the replication of what would be a dawn.