Eclipse August 12, 2026 · Madrid / Segovia, Spain
Will mountains block your eclipse view from Sierra de Guadarrama?
The southern edge of the path of totality crosses the Guadarrama range — Madrid city itself misses totality, but the mountains 50 km north of it don't. Totality is short here (40–70 seconds) and grows as you move north-west, so both the path edge AND the 2,400 m ridgeline matter when picking a spot.
The August 12, 2026 total solar eclipse over Sierra de Guadarrama happens at very low sun altitude — under 10° in many places. At that altitude, even modest hills or ridges in your western horizon can block the sun completely. Every vantage point below has been pre-checked: we ray-cast the real terrain horizon from its exact coordinate and report whether the eclipsed sun clears the ridge line, with a link to the live 3D simulation to verify your own spot.
Each verdict is computed by ray-casting 360° from the exact coordinate over Mapbox Terrain-RGB elevation data (30 km range) — the same engine as the live 3D sky view. Margins under ~1° are flagged marginal: elevation pixels are ~75 m wide and can miss sharp ridge lines, and trees or buildings are not included.
Key viewpoints
Puerto de Navacerrada Clear view at totality
40.787°N, -3.990°W
The sun clears the terrain by 7.5° at the critical moment. Terrain hides the sun at 21:18 — before the partial phase ends at 21:23.
Check terrain in 3D →Peñalara Clear view at totality
40.850°N, -3.957°W
The sun clears the terrain by 7.6° at the critical moment. Terrain hides the sun at 21:18 — before the partial phase ends at 21:23.
Check terrain in 3D →La Granja de San Ildefonso Clear view at totality
40.900°N, -4.006°W
The sun clears the terrain by 7.7° at the critical moment. Terrain hides the sun at 21:19 — before the partial phase ends at 21:23.
Check terrain in 3D →Rascafría Blocked by terrain
40.905°N, -3.878°W
The terrain rises 2.3° above the sun — the eclipse is hidden behind the ridge from this spot. Terrain hides the sun at 20:21 — before the partial phase ends at 21:23.
Check terrain in 3D →Cercedilla Blocked by terrain
40.741°N, -4.056°W
The terrain rises 3.8° above the sun — the eclipse is hidden behind the ridge from this spot. Terrain hides the sun at 20:15 — before the partial phase ends at 21:24.
Check terrain in 3D →Drop a pin anywhere — Heliora computes the terrain horizon from that exact point and shows whether the eclipsed sun is visible above it.
Why does terrain matter so much?
- How low will the sun be during the eclipse?
- Across most of Spain the sun will be between 4° and 12° above the horizon at maximum eclipse. At 4°, a 100 m ridge half a kilometre away blocks the sun. At 8°, the same ridge needs to be 1.4 km away to clear it.
- How does Heliora know the actual horizon from my spot?
- Heliora downloads Mapbox Terrain-RGB elevation tiles around your pin and ray-casts 360° outward, sampling elevation every degree of azimuth and computing the apparent angle of the highest point. The result is the real local horizon from your exact GPS coordinate, not the flat-earth horizon.
- Does this work for buildings too?
- Yes — toggle the "buildings" layer in the sky view. Heliora pulls Mapbox 3D building data for the closest 2 km and renders them as occluders. This is critical in cities like Bilbao, Santander, or Madrid where city blocks can hide a low sun.
- Why did you build this?
- Generic eclipse tools tell you the sun's altitude but not whether your real horizon clears it. For a low-altitude eclipse like 2026-08-12 in Spain, that distinction is the difference between seeing totality and seeing nothing at all from a mountain valley.