When does it get dark in Porto tonight?

Tonight's darkness times for Porto depend on the date and Porto's latitude (41.2°). Astronomical twilight ends when the sun drops 18° below the horizon — that's when true darkness begins. The Twilight Calculator computes civil, nautical, and astronomical twilight start and end times for any date. Enter Porto as your location above and press Calculate to see the exact times for tonight.

How long does astronomical twilight last in Porto?

Astronomical twilight duration at Porto varies by season. At 41.2° latitude (mid-latitude), it typically lasts 90–120 minutes during equinox periods. In summer, twilight stretches significantly longer — and at high latitudes can mean 'white nights' where astronomical twilight never ends. In winter, the steeper sun angle produces shorter twilight. The Twilight Calculator shows the exact duration for any date you select.

What is the best time for stargazing in Porto?

The best stargazing in Porto occurs when two conditions align: astronomical twilight has ended (sun > 18° below horizon) and the moon is near new moon or below the horizon. At 41.2° latitude, the longest dark-sky windows occur during the October–March months. Use the Twilight Calculator to find tonight's dark window, then cross-reference with MoonSync to check the moon phase — this gives you the 'astrophotographer's golden hours' for Porto.

Does Porto experience white nights?

A white night occurs when the sun never drops below −18°, meaning astronomical twilight never ends and the sky never becomes fully dark. At Porto's latitude of 41.2°, 41.1579° is below the white night threshold — the sun always drops below −18° and true darkness occurs every night. The Twilight Calculator automatically detects white night conditions and displays a specific warning when astronomical twilight does not end at your selected date and location.

Dämmerungsdaten für Porto

Dämmerungszeiten Porto — Twilight Calculator · FastTool

How Twilight Works at Porto's Latitude

Twilight Duration at Porto

At Porto's latitude of 41.2°, 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 Porto's dark-sky window so different month to month.

Porto liegt in der südlichen Hälfte des Pfads der totalen Sonnenfinsternis vom 12. August 2026 — die Totalität wird etwa 1 Minute 45 Sekunden über der ikonischen Dom-Luís-I-Brücke und dem Douro-Tal dauern. Die engen Gassen des UNESCO-gelisteten Ribeira-Viertels werden in eine unheimliche Mittagsdunkelheit fallen, während der Mondschatten mit über 2.000 km/h vom Atlantik her landeinwärts rast.

NOAA Twilight Reference

When Does It Get Truly Dark in Porto?

At Porto, true astronomical darkness begins when the sun drops more than 18° below the horizon — the end of astronomical twilight. At 41.2° latitude, this dark window varies from approximately 4–6h in summer to 12–14h in winter. During the October–March months, Porto 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.

Porto auf 41,2°N ist in atlantisches Licht getaucht — die berühmte goldene Nachmittagssonne, gefiltert durch maritimen Dunst, inspiriert seit Jahrhunderten Maler und Fotografen. Die nach Westen ausgerichtete Lage der Stadt an der Douro-Mündung bedeutet, dass jeder Sonnenuntergang ein Schauspiel ist, eingerahmt von Fluss, Ozean und den terrassierten Hügeln von Vila Nova de Gaia am gegenüberliegenden Ufer.

ESO — Twilight Reference

Civil, Nautical & Astronomical Twilight Explained

Three twilight phases occur each evening and morning at Porto, 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 Porto's latitude, these phases progress at different speeds depending on the season — faster near the equinoxes and slower near the solstices.

IAU — Twilight Definitions

Jean Meeus Algorithm & Accuracy

The Twilight Calculator for Porto 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 Porto's coordinates.

US Naval Observatory — Astronomical Applications

22:19

Vollständig Dunkel

02:53

Astro-Dämmerung

4h 34.06220000000002m

Dunkelfenster

20:44

Bürgerl. Dämmerung

Frequently Asked Questions About Twilight in Porto

When does it get dark in Porto tonight?: Tonight's darkness times for Porto depend on the date and Porto's latitude (41.2°). Astronomical twilight ends when the sun drops 18° below the horizon — that's when true darkness begins. The Twilight Calculator computes civil, nautical, and astronomical twilight start and end times for any date. Enter Porto as your location above and press Calculate to see the exact times for tonight.
How long does astronomical twilight last in Porto?: Astronomical twilight duration at Porto varies by season. At 41.2° latitude (mid-latitude), it typically lasts 90–120 minutes during equinox periods. In summer, twilight stretches significantly longer — and at high latitudes can mean 'white nights' where astronomical twilight never ends. In winter, the steeper sun angle produces shorter twilight. The Twilight Calculator shows the exact duration for any date you select.
What is the best time for stargazing in Porto?: The best stargazing in Porto occurs when two conditions align: astronomical twilight has ended (sun > 18° below horizon) and the moon is near new moon or below the horizon. At 41.2° latitude, the longest dark-sky windows occur during the October–March months. Use the Twilight Calculator to find tonight's dark window, then cross-reference with MoonSync to check the moon phase — this gives you the 'astrophotographer's golden hours' for Porto.
Does Porto experience white nights?: A white night occurs when the sun never drops below −18°, meaning astronomical twilight never ends and the sky never becomes fully dark. At Porto's latitude of 41.2°, 41.1579° is below the white night threshold — the sun always drops below −18° and true darkness occurs every night. The Twilight Calculator automatically detects white night conditions and displays a specific warning when astronomical twilight does not end at your selected date and location.

30-Tage-Beobachtungsplaner

Datum	Sonnenaufgang	Sonnenuntergang	Dämmerungsende	Mondbeleucht.	Dunkelfenster
Jun 21Heute	05:03	20:11	22:19	40%	4h 34m
Jun 22	05:03	20:11	22:19	50%	4h 34m
Jun 23	05:03	20:12	22:19	61%	4h 34m
Jun 24	05:03	20:12	22:19	70%	4h 35m
Jun 25	05:03	20:12	22:19	79%	4h 35m
Jun 26	05:04	20:12	22:19	86%	4h 36m
Jun 27	05:04	20:12	22:19	92%	4h 36m
Jun 28	05:04	20:12	22:19	96%	4h 37m
Jun 29	05:05	20:12	22:18	99%	4h 38m
Jun 30	05:05	20:12	22:18	100%	4h 39m
Jul 1	05:06	20:12	22:18	99%	4h 40m
Jul 2	05:06	20:12	22:17	96%	4h 41m
Jul 3	05:07	20:12	22:17	92%	4h 43m
Jul 4	05:07	20:12	22:16	86%	4h 44m
Jul 5	05:08	20:11	22:15	77%	4h 46m
Jul 6	05:08	20:11	22:15	68%	4h 47m
Jul 7	05:09	20:11	22:14	57%	4h 49m
Jul 8	05:09	20:11	22:13	46%	4h 51m
Jul 9	05:10	20:10	22:12	35%	4h 53m
Jul 10	05:11	20:10	22:12	25%	4h 55m
Jul 11	05:11	20:09	22:11	15%	4h 57m
Jul 12	05:12	20:09	22:10	8%	4h 59m
Jul 13	05:13	20:08	22:09	3%	5h 2m
Jul 14	05:14	20:08	22:08	0%	5h 4m
Jul 15	05:14	20:07	22:06	1%	5h 6m
Jul 16	05:15	20:07	22:05	4%	5h 9m
Jul 17	05:16	20:06	22:04	9%	5h 11m
Jul 18	05:17	20:06	22:03	17%	5h 14m
Jul 19	05:18	20:05	22:02	25%	5h 17m
Jul 20	05:18	20:04	22:00	35%	5h 19m