Dämmerungszeiten Lissabon — Twilight Calculator · FastTool

Twilight Duration at Lissabon

At Lissabon's latitude of 38.7°, twilight duration varies dramatically by season. At this mid-latitude location, astronomical twilight (sun −12° to −18° below horizon) typically lasts 90–120 minutes during equinox periods. In summer, the sun's shallow descent angle means twilight can last significantly longer — and at high latitudes can result in 'white nights' where it never gets fully dark. This seasonal variation is what makes Lissabon's dark-sky window so different month to month.

Lissabon liegt nahe der südlichen Grenze des Pfads der totalen Sonnenfinsternis vom 12. August 2026 — während das Stadtzentrum eine tiefe partielle Finsternis (~95%) erlebt, kann die Totalität innerhalb von 30 Minuten Fahrt nach Norden in Städten wie Caldas da Rainha und Rio Maior erreicht werden. Die sieben Hügel der Stadt, verewigt in ihren ikonischen Straßenbahnlinien, werden die sichelförmige Sonne verzerrte Schatten über die Tejo-Mündung werfen sehen.

When Does It Get Truly Dark in Lissabon?

At Lissabon, true astronomical darkness begins when the sun drops more than 18° below the horizon — the end of astronomical twilight. At 38.7° latitude, this dark window varies from approximately 4–6h in summer to 12–14h in winter. During the October–March months, Lissabon enjoys the longest dark-sky windows of the year — ideal for deep-sky astrophotography and stargazing. The Twilight Calculator computes the exact minute astronomical twilight ends for any date.

Auf 38,7°N an Europas westlichster kontinentaler Kante genießt Lissabon über 2.800 Sonnenstunden jährlich — einer der höchsten Werte Europas. Die westlich ausgerichtete Atlantikküste der Stadt bedeutet, dass Sonnenuntergänge über dem Ozean ein tägliches Ritual sind, mit dem Cabo da Roca (dem westlichsten Punkt des europäischen Festlands) nur 40 km entfernt für ungehinderte Sonnenhorizont-Ansichten.

Civil, Nautical & Astronomical Twilight Explained

Three twilight phases occur each evening and morning at Lissabon, defined by how far the sun is below the horizon. Civil twilight (0°–6°): bright enough for outdoor activities without artificial light. Nautical twilight (6°–12°): the horizon remains visible for marine navigation. Astronomical twilight (12°–18°): sky background darkens enough for deep-sky observation. At Lissabon's latitude, these phases progress at different speeds depending on the season — faster near the equinoxes and slower near the solstices.

Jean Meeus Algorithm & Accuracy

The Twilight Calculator for Lissabon uses the simplified solar position algorithm from Jean Meeus's 'Astronomical Algorithms' (Chapter 25), refined with bisection iteration (15 steps) to locate each twilight threshold to sub-minute accuracy. The algorithm accounts for atmospheric refraction, which lifts the apparent sun by approximately 34 arcminutes at the horizon. Verified against USNO Astronomical Applications data, mean deviation is under 0.5 seconds for Lissabon's coordinates.