Total solar eclipse of 2 August 2027: where and how to watch it safely

The path of totality: from the Strait of Gibraltar to the Red Sea

Of the 68 total solar eclipses of the 21st century, only one lasts longer than that of Monday 2 August 2027. That day, the Moon will cover the Sun completely for up to 6 min 23 s, according to Fred Espenak’s calculations for NASA [1]. Only the eclipse of 22 July 2009 did better, with 6 min 39 s: we went through his tables decade by decade [2], and the US National Solar Observatory reaches the same ranking [3].

The Moon’s shadow first touches the Earth over the Atlantic, crosses the Strait of Gibraltar, runs along the North African coast, sweeps across Egypt and the Red Sea, grazes Saudi Arabia, Yemen and the north-eastern tip of Somalia, then fades out over the Indian Ocean [4]. In North Africa it passes over Morocco, Algeria, Tunisia and Libya [3]. In Europe, totalityThe phase when the Moon completely hides the Sun’s bright disc. It can only be seen inside a narrow band, the path of totality; everywhere else, the eclipse remains partial. touches only Gibraltar [3], a British Overseas Territory, and the southern tip of Spain: Ceuta, Melilla, almost all of the province of Cádiz, much of the province of Málaga and the far south of the provinces of Granada and Almería, according to Spain’s National Geographic Institute (IGN) [4].

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The path is about 240 km wide over the Strait, and a little over 250 km wide in Egypt [5]. It is in Upper Egypt, under an almost vertical Sun, that totality lasts longest: 6 min 23 s on the centre line south of Asyut, and 6 min 22 s at the point of greatest eclipse, east of Luxor, where the Sun stands 82° high [5]. In Luxor itself, Egypt’s National Research Institute of Astronomy and Geophysics (NRIAG) announces more than 6 minutes of totality, from 1.02pm local time [6].

Times and durations of totality, place by place

How long it lasts depends on where you stand in the path: longest on the centre line, it shrinks towards the edges, down to a few seconds. Málaga, near the northern edge, will get only 1 min 48 s of totality, while Tarifa gets 4 min 38 s and Ceuta 4 min 48 s, the Spanish record [4]. The detail that changes everything: Almería lies just north of the limit. The IGN gives it a magnitudeThe share of the Sun’s diameter covered by the Moon at maximum eclipse: 0.50 for half the diameter, more than 1 during totality. of 1.00, rounded to two decimal places, but not a single second of totality [4].

Before and after, the partial phase lasts more than an hour on each side: in Cádiz, the Moon takes its first bite out of the Sun at 9.41am and leaves it at 11.59am [4]. For any other Spanish town, the IGN’s online viewer gives the times to the second.

What you will see during totality, and why 99% is not enough

Anyone who has waited up for the northern lights knows the uncertainty; totality, by contrast, turns up on the dot. But it is not the night you might picture. With 99% of the Sun covered, it is still daytime: about 1,000 lux, the light of an overcast day, reports the American Astronomical Society (AAS). Everything changes in the final minute: during totality, the light falls to around 5 lux, that of twilight, with a sunset glow all round the horizon [9].

The signs come well before. Once more than three-quarters of the Sun is covered, the light takes on an odd tint, the temperature drops, the wind may shift, and birds and insects behave as if evening were falling [10]. If you enjoy counting garden birds, watch how they react. Then come Baily’s beads, the last glints of sunlight through the valleys on the Moon’s edge, the diamond ring, and finally the corona, the Sun’s outer atmosphere, glowing around the black disc [10]. In Luxor, Venus will shine about 3° from the Sun [6].

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Outside the path: the partial eclipse from the UK and Europe

Outside the path, the eclipse is partial over almost all of Europe, much of Africa and south-west Asia [4]. In the UK, the Moon will cover anything from 27% of the Sun in Edinburgh to 46% in Plymouth; in London, 42%, at 10am BST. Everywhere in Britain and Ireland, maximum eclipse comes at around 10am, give or take a few minutes [8].

A partial eclipse, even at 75%, does not bring night: until three-quarters of the Sun is covered, your pupils compensate so well that you barely notice the light fading [10]. And from the first minute to the last, the Sun should only be viewed through proper eclipse glasses [11]. In the United States, by contrast, the eclipse will not be visible at all, not even as a partial one [1, 8].

Protecting your eyes: ISO 12312-2 glasses and nothing else

An eclipse does not make the Sun any less dangerous, only more tempting to look at. And the retina gives no warning: a burn does not hurt, as the European Space Agency (ESA) and the IGN point out [12, 13]. The damage can be permanent, stresses Germany’s Federal Office for Radiation Protection (BfS) [14], and the symptoms, blurred vision or a blind spot in the centre of your field of view, sometimes appear only hours or days later, warns the Spanish government’s official website [7].

When can you take your glasses off? Only inside the path, during totality, once no part of the Sun can be seen through them [15]. At the first flash of returning sunlight, the diamond ring, they go straight back on [7]. Outside the path, that moment never comes: from first contact to last, the glasses stay on [11].

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The rest of the time, the rules are the same everywhere, as set out by NASA, the AAS, ESA and the BfS:

• Eclipse glasses that meet the ISO 12312-2 standard, with ‘EN ISO 12312-2:2015’ on the frame, packaging or instructions, and the CE mark if they are sold in the European Union [7, 14]. A reference to ‘ISO 12312-1’ means ordinary sunglasses [7].
• Never sunglasses, however dark, and no home-made filters: smoked glass, X-ray film, CDs, kitchen foil, photographic film [11, 12, 13]. A proper solar filter cuts visible light by a factor of at least 30,000 [13].
• Undamaged glasses: if they are scratched, punctured, torn or coming away from the frame, throw them away [11].
• No instrument without its own filter: looking at the Sun through binoculars, a telescope or a camera viewfinder without a solar filter fixed to the front instantly causes severe eye injury, and eclipse glasses give no protection behind an instrument [15].
• Children supervised, and your own spectacles kept on under the eclipse glasses [11].

How can you tell whether a pair is safe? You can’t, says the AAS; you can only spot the ones that aren’t: worn indoors, they should let nothing through except a very bright lamp, much dimmed [16]. So buy them from a recognised manufacturer or dealer; the AAS keeps a checked list [16]. Good news for anyone who kept their glasses from August 2026: according to the AAS, compliant glasses less than 10 years old and in perfect condition can be used again [11]. Just check the expiry date that some manufacturers print [7].

No glasses? Projection, the only safe improvised method

No glasses? Don’t look at the Sun, look at the ground. With your back to the Sun, a small hole in a piece of card, the holes of a colander or the gaps between the leaves of a tree cast lots of little crescent Suns on the ground or a wall [11, 15]. The BfS regards projection as the safest method of all [14]. Just one rule: never look at the Sun through the hole [11].

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Weather on 2 August: what the statistics say

Nobody can forecast the sky for 2 August 2027 today: the IGN points to the forecasts of Spain’s state weather agency, AEMET, a few days beforehand [19]. Statistics, however, do exist, and they are encouraging. For Jay Anderson, who specialises in eclipse weather and runs the Eclipsophile website, the cloud expected along this track is among the lowest he has analysed in 45 years [20].

In Spain, the main risk comes from the sea: in the morning, low cloud and sea mist can linger on the Atlantic coast. On satellite images taken as close as possible to the time of totality, from 12 July to 18 August 2024 and 2025, Jay Anderson saw the Sun on 88% of days in Cádiz, against an average of 74% for three sites further south, including Atlanterra and Tarifa. His advice: move a little way inland, where average cloud cover drops below 15%, while the Mediterranean coast towards Marbella usually escapes the Atlantic cloud [20]. The IGN, working from average August cloud cover between 2001 and 2017, also describes a fairly cloud-free area, only slightly cloudier in the west of the province of Cádiz, where humid Atlantic air comes in [19].

Further east, Egypt is close to a sure thing: in Luxor, the main threat is thin cirrus. The heat, on the other hand, is guaranteed: in Luxor, the maximum temperature on 2 August has averaged 42 °C over the past 17 years, with a record of 46 °C [20]. In southern Spain too, an August morning in full sun takes some planning: shade, water, a hat [17].

All that remains is to choose: the Strait and its 4-plus minutes, the hills behind Cádiz, clear of the sea mist, or Luxor, its temples and its 6 minutes under an almost vertical Sun. Whichever you pick, slip a pair of compliant glasses into your rucksack, keep an eye on the final forecasts, and let yourself be caught by that rare moment when, on a summer morning, the day holds its breath.

Worth watching

NASA’s Goddard Space Flight Center shows, step by step, how to turn a cereal box into a pinhole projector, so you can watch the partial phases on a screen without ever looking at the Sun.

The video is hosted by YouTube (Google): nothing loads until you play it, and Google may then set cookies.

Nolwenn Bastide

Trail running, snow, water, nature and destinations

Nolwenn covers trail running, snow, water, nature and destinations for Outfarer. Curious about everything, from meteor showers to night-train timetables, she has a knack for unearthing the one detail that changes everything, and putting it in a single sentence.

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