The official map is unambiguous: 3,963 municipalities sit inside the band where the Moon will fully cover the Sun on 12 August 2026. Being inside that band, though, is a geometric fact about the sky — it says nothing about what’s standing between you and the horizon. Because this eclipse happens at sunset, with the Sun sitting as low as 2° to 12° above the skyline, a modest ridge to the west is enough to swallow the whole show before it starts.
Our scoring model — the same one that colours the “terrain” layer on the map and feeds the score chip in the municipality table — checks exactly that: it compares the Sun’s altitude at maximum eclipse against the elevation angle of the real digital terrain model to the west, point by point. In 85 of the 3,963 towns, the horizon wins. The dataset flags them explicitly with a visibility flag set to false — not a rounding artefact, a direct output of the pipeline.
Where the horizon wins
The 85 towns aren’t scattered evenly. They cluster in mountainous terrain that happens to sit inside the band’s diagonal path across Spain:
- Castelló/Castellón — 18 towns, the single largest concentration, in the folded interior ranges (Maestrazgo, Els Ports) rather than the flat coast.
- Tarragona — 17 towns, dominated by the Ports de Tortosa-Beseit massif.
- Illes Balears — 17 towns, mostly in Mallorca’s Serra de Tramuntana.
- Madrid — 6 towns, in the Sierra de Guadarrama foothills.
- Asturias — 5 towns, deep in the Cordillera Cantábrica.
- The remaining 22 are spread thinly across Cantabria, Teruel, Zaragoza, Navarra, La Rioja, Bizkaia, Guadalajara, Gipuzkoa, León, Lugo, Soria, Araba/Álava and València — one or two towns each, wherever a local ridge happens to line up with the sunset azimuth of 279°–288°.
The extremes are stark. Alfara de Carles, in Tarragona’s Ports massif, has a margin of −6.4° — the Sun would need to climb more than six degrees higher than it ever will to clear the ridge. Roquetes, a few kilometres away, sits at −5.6°. Posada de Valdeón, tucked into the Picos de Europa in León, and Cillorigo de Liébana, its Cantabrian neighbour across the same valley, both sit at exactly −5°. At the other end of the list, a handful of towns miss out by a hair: Villamalur (Castellón), Sabiñán and Sestrica (both Zaragoza) carry a margin of just +0.1° — a positive number, and still flagged as blocked. That’s not a rounding artefact: the pipeline requires a margin greater than 0.25° — the Sun’s own apparent angular radius — to flag a town as visible, not just a positive margin. At +0.1° the CENTRE of the solar disk would already clear the ridge, but the full disk (half a degree across) still gets clipped at the top at the moment of maximum eclipse. Twenty of the 85 towns fall into this near-miss category, with a margin between 0.0° and 0.25° — enough for the Sun’s centre, not enough for the whole disk.
The cruellest cases
What makes this list sting is that several of these towns aren’t marginal eclipses to begin with. Riosa, in the Asturian interior, would have had 109 seconds of totality — one second short of El Franco’s national record of 110s — if its own hills didn’t stand in the way, at a margin of −4.4°. Averaged across all 85 blocked towns, the eclipse they’re missing would have lasted 84 seconds, with a low of 16s and a high of 109s. This isn’t a list of towns on the fringe of totality; several of them are sitting on some of the best geometry in the country, undone entirely by what’s due west.
Navarredonda y San Mamés, above Madrid’s Sierra de Guadarrama, and Alaró, under Mallorca’s Serra de Tramuntana at a Sun altitude of just 3°, round out a pattern that repeats across the list: it is almost always mountains close to the coast or a shielded valley, not distance from the eclipse’s centreline, that decides who sees it.
What this means if you’re planning to travel
The lesson isn’t “avoid these 85 towns” in the abstract — it’s that the totality band on a map is necessary but not sufficient. If your destination sits in a valley, below a ridge, or on the eastern slope of anything taller than a few hundred metres, the terrain check matters more than the band check. Use the “Your town” search on the map above: it runs this exact horizon comparison for any point in Spain, not just the 3,963 towns already scored, and shows you the silhouette of what’s actually to your west.