UK Solar Eclipse 2026: The Deep Partial Eclipse of August 12, Explained

A solar eclipse happens when the Moon passes between the Sun and Earth and casts its shadow onto Earth’s surface. Astronomers classify every solar eclipse into one of four types based on how completely the Moon covers the Sun as seen from a given spot: total (the Moon fully covers the Sun, revealing the corona), annular (the Moon is too far from Earth to fully cover the Sun, leaving a bright ring, or “ring of fire”), partial (the Moon covers only part of the Sun), and hybrid (a rare eclipse that shifts between annular and total along its path). “Deep partial” is not a fifth official category — it’s a descriptive, commonly used term (including by the Royal Astronomical Society and BBC Sky at Night Magazine in their coverage of this event) for a partial eclipse in which an unusually large fraction of the Sun’s visible disc is obscured, as opposed to a shallow partial eclipse covering only a small bite.

On 12 August 2026, the Moon’s shadow does produce a total eclipse — just not over the UK. The dark inner shadow (the umbra) sweeps across Greenland, Iceland and northern Spain; anyone standing inside that narrow track sees a true total eclipse. The UK sits outside the umbra’s path entirely, inside the much larger surrounding penumbra, so every UK observer sees a partial eclipse. What makes this particular partial eclipse “deep” is simply proximity: the UK is close enough to the edge of the umbra’s path that the fraction of the Sun covered climbs unusually high — up to 96.5% in the far southwest — without ever quite reaching 100%.

Magnitude vs obscuration — the distinction that matters

Two different numbers get used, often interchangeably, to describe “how much of the Sun” an eclipse covers, and they are not the same measurement. Magnitude is the fraction of the Sun’s diameter covered by the Moon at maximum eclipse, measured along the line connecting the centres of the two discs. Obscuration is the fraction of the Sun’s visible area (its disc, as a two-dimensional shape) covered. For London on 12 August 2026, the magnitude is about 0.92 (the Moon covers 92% of the Sun’s diameter) while the obscuration is closer to 91% (91% of the Sun’s area). The two numbers converge as an eclipse approaches totality but diverge more at lower coverage — a 50% obscuration figure, for instance, does not mean the Moon has moved exactly halfway across the Sun’s diameter, and does not mean sunlight reaching the ground has dropped by half either, since the human eye and most light sensors respond non-linearly to partial obscuration of a very bright source. Coverage figures quoted in this guide are obscuration percentages except where a source explicitly gives magnitude only, which is noted in the city table below.

The pattern that surprises most people: coverage generally increases toward the west and southwest of the UK and decreases toward the northeast. That’s the opposite of the 2015 UK eclipse, where coverage was deepest in the far north of Scotland. It happens because this eclipse’s path of totality runs from Greenland through Iceland to Spain — a track that lies southwest of the UK, so the parts of Britain and Ireland closest to that track (the southwest of England, west Wales, Northern Ireland) see the Moon positioned more centrally over the Sun than locations further northeast.

Reading the blank cells: where this table shows a dash rather than a duplicated or estimated figure, that specific number wasn’t independently confirmed across the primary and secondary sources checked for this guide (listed in full under Astronomical Data Sources below). Rather than back-calculate an obscuration percentage from magnitude — which would blur a real measurement with an approximation — use the Magnitude column together with the regional pattern described above, or look up the location directly on NASA’s interactive eclipse map or timeanddate’s eclipse calculator, both linked in the sources section, for an exact figure.

Three factors set how deep the eclipse looks from any given UK spot: longitude (how far west, since the umbra’s track runs through the North Atlantic west of the UK — further-west locations sit closer to that track), latitude (a smaller effect here, mostly interacting with longitude to shape the coverage gradient across the country) and local horizon (since the Sun is only 9–15° above the horizon at maximum everywhere in the UK, a genuinely open view to the west or west-northwest matters more for actually seeing the event than the coverage percentage itself). A location with 90% obscuration and a clear sea horizon to the west will often give a better practical view than a 93% location boxed in by buildings or hills in that direction.

London sees the eclipse begin at 6:17pm BST, reach maximum around 7:13pm, and end by 8:06pm — a partial phase lasting about 1 hour 49 minutes. At maximum, the Moon covers roughly 91% of the Sun’s disc (magnitude 0.92), with the Sun sitting about 10° above the west-northwest horizon. Sunset in London that evening is around 8:31pm, so the eclipse ends roughly 25 minutes before the Sun actually sets — low enough that tall buildings, trees or hills to the west can easily block the view, so an open sightline toward the west-northwest is essential. This will be the deepest solar eclipse visible from the capital since the total eclipse of 1999, when London itself saw about 96.8% coverage without reaching totality.

Scotland’s coverage sits in a narrower band than England’s — roughly 88–91.5% nationwide, with Glasgow slightly deeper than Edinburgh and the far northeast (Shetland, around 88%) the shallowest anywhere in the UK. Scotland also sees maximum eclipse earliest in the country, shortly after 7pm, and enjoys the highest Sun altitude at maximum of anywhere in the UK — still low, but a few degrees higher than in southern England, since sunset itself comes later at this latitude in August.

Wales sees some of the deepest coverage in the UK outside Cornwall’s tip. Cardiff reaches about 93.2% obscuration at maximum (19:13 BST), and Swansea, further west, is expected to be similar or very slightly higher (magnitude 0.942, among the highest confirmed magnitude values in this guide’s city table), with the Sun around 12–13° above the west-northwest horizon at both. Wales’s western coastline gives many locations an open sea horizon in the right direction, which is a genuine practical advantage for this low-altitude, near-sunset event.

Belfast sees the eclipse begin at 18:10 BST, reach maximum around 19:08, and end by 20:03 — with obscuration around 93.1%, among the deepest confirmed figures anywhere in the UK. Northern Ireland’s westerly position within the British Isles places it close to the same favourable geometry that deepens the eclipse across Wales and southwest England.

England shows the widest spread of any UK nation, from around 90–91% across the Midlands, North and East (Leeds, Newcastle, Nottingham, Cambridge) to 92–96.5% across the Southwest (Bristol, Southampton, and up to the Isles of Scilly and Cornwall’s tip). London and the Southeast sit in between, around 91%. See the full city-by-city table above for exact figures; as a rule of thumb, the further southwest the location, the deeper the eclipse and the more likely a clear sea horizon toward the west-northwest.

A solar eclipse is a straightforward alignment problem: the Moon orbits Earth, and when a new Moon happens to fall directly between the Sun and Earth, the Moon’s shadow sweeps across part of Earth’s surface. That shadow has two distinct parts. The umbra is the small, dark, central cone of shadow inside which the Sun is completely blocked — anyone standing inside it sees a total eclipse. The penumbra is the much larger, lighter, outer shadow inside which the Moon blocks only part of the Sun — anyone standing inside it sees a partial eclipse, with the fraction covered increasing the closer they are to the umbra’s edge. (A third term, the antumbra, applies only to annular eclipses, where the Moon is too far from Earth for its umbra to reach the ground at all; it isn’t relevant to this event.)

On 12 August 2026, the umbra’s narrow, 294km-wide path runs from Greenland through Iceland to Spain. The UK sits entirely within the penumbra — close enough to the umbra’s edge to see a very high percentage of the Sun covered, but never inside it. That single geometric fact is the entire reason this is a deep partial eclipse for Britain and Ireland rather than a total one: distance from the umbra’s track, nothing more exotic.

Through certified eclipse glasses, the Sun will appear as a shrinking crescent over roughly 100 minutes, from a nearly full disc at first contact to a thin sliver at maximum, then widening again as the Moon moves off. With the naked eye (unprotected, which is never safe to actually try), the Sun’s brightness barely changes to human perception until coverage gets very high, because human vision compresses an enormous range of brightness — even at 90% obscuration, the remaining 10% of the Sun is still far too bright to look at directly and still floods the sky with plenty of light.

Visible, safe-to-notice effects at this level of coverage include: a perceptible dimming and cooling of the light, similar to an overcast day, more pronounced as coverage climbs past 90%; sharper, slightly odd-coloured shadows; and, if you have leafy trees nearby, dozens of small crescent-shaped patches of light on the ground under the canopy — the gaps between leaves acting as natural pinhole projectors. A simple pinhole projector (a pierced card held up to project the Sun’s image onto a second card) shows the same crescent shape safely and clearly. Because the UK never reaches totality, do not expect full darkness, visible stars, a corona, or the dramatic temperature drop associated with a total eclipse — those effects require the Sun’s disc to be completely covered, which does not happen anywhere in Britain or Ireland on this date.

Certified eclipse glasses meet the international safety standard ISO 12312-2, printed on genuine products; buy from a reputable optical, astronomy or museum retailer rather than an unverified online marketplace listing, since counterfeit “ISO 12312-2” glasses have been documented in past eclipse cycles. Before use, hold them up to an ordinary household lamp: you should see nothing or, at most, an extremely faint filament — if you can see the room clearly, do not use them to view the Sun.

Cameras, camcorders, and phone cameras face the same risk as human eyes, and in one respect a worse one: a telescope, telephoto lens or binoculars concentrates sunlight the way a magnifying glass concentrates it onto paper, and can damage a camera’s sensor or a phone’s tiny lens and sensor stack within seconds without a proper solar filter fitted over the front element. A plain smartphone camera without an attachment is somewhat less concentrated optically, but still risks lens flare artefacts, sensor damage on some devices at high zoom, and — more practically — does a poor job of capturing a partial eclipse at all without a solar filter, since the Sun will simply appear as an overexposed white blob.

To photograph the eclipse: fit a certified solar filter (glass or polymer, rated for direct solar photography) over the front of any lens before pointing it anywhere near the Sun, never behind the lens near the sensor. A basic option for phones is a purpose-made solar filter clip, again ISO 12312-2 rated for solar viewing/photography; without one, photograph the ground effects instead — pinhole crescents under trees, changing light quality — which need no special filter at all.

Children can safely enjoy this eclipse with the same precautions as adults, plus active supervision. Fit eclipse glasses on a child yourself and check the fit doesn’t let light in around the edges; young children are often more interested in the glasses as a toy than in looking at the Sun through them for long, so keep viewing sessions short and supervised throughout, not just at the start. Pinhole projection is an excellent alternative for younger children, since it requires no eyewear at all and turns the eclipse into a simple, safe, hands-on activity — a colander held up to project dozens of tiny crescents onto the pavement works just as well as a purpose-made projector. Never assume a child is using glasses correctly without checking; briefly and repeatedly confirm they are looking through the filter, not around it.

This page cannot tell you whether it will be cloudy in your town on 12 August 2026 — that is a forecast question, not an astronomy one, and only becomes reliable a few days out. What can be said now, as general climatology rather than a forecast: mid-August in the UK typically brings a mix of conditions, and any single evening’s cloud cover is highly variable and impossible to predict with confidence more than about a week in advance. Historically, UK eclipse-watchers have had mixed luck — the 1927 total eclipse over Lancashire and Yorkshire was mostly cloud-obscured, while 1999 saw a mix of clear and overcast skies along the path of totality.

Because this eclipse sits low on the western horizon, low cloud, haze or obstructions near the horizon matter more than high overhead cloud cover — a location with a clear sky overhead but a bank of cloud sitting on the western horizon may still miss the event, while a spot with some high cloud but a clear western horizon may see it well. Check a short-range (1–3 day) forecast from the Met Office or a similar official source close to the date, and if your local forecast looks poor, consider that a livestream (see below) guarantees a view regardless of local weather.

This guide has not been able to confirm a specific, dated UK public livestream beyond NASA’s own broadcast at the time of writing; check the organisations below closer to 12 August rather than relying on a stream not yet announced.

None of the next four UK-visible eclipses comes close to 12 August 2026’s depth of coverage. For a genuinely comparable or deeper UK partial eclipse, the wait is considerably longer than for the next total eclipse anywhere in the UK — which itself isn’t until 2090, sixty-four years from now.

The UK gets both types of eclipse in close succession this year: this deep partial solar eclipse on 12 August, followed by a 90% partial lunar eclipse on 28 August 2026 (maximum around 5:12am BST) — unlike the solar eclipse, the lunar eclipse needs no eye protection at all and can be watched directly.

These four types describe the same underlying geometry viewed from different distances and positions — none is scientifically “better” than another; a partial eclipse is not an inferior or failed total eclipse, just a different vantage point on the same alignment.

The Moon passes between the Sun and Earth every month at new Moon — so why isn’t there a solar eclipse every month? Because the Moon’s orbit is tilted about 5° relative to Earth’s orbital plane (the ecliptic). Most months, the new Moon passes slightly above or below the Sun as seen from Earth, missing it entirely. An eclipse can only happen when new Moon coincides with the Moon crossing the ecliptic plane, at one of two points called nodes. These alignment windows, called eclipse seasons, recur roughly twice a year, about 173 days apart — which is why solar eclipses (and lunar eclipses at full Moon) cluster around two periods each year rather than spreading evenly across twelve months.

A few figures make the mechanics behind 12 August 2026 concrete. The synodic month — the time from one new Moon to the next — averages about 29.5 days, setting the rhythm of possible eclipse dates. The Sun’s apparent diameter in the sky varies only slightly through the year (Earth’s orbit is nearly circular), while the Moon’s apparent diameter varies more, since its orbit around Earth is more elliptical; whether an eclipse is total or annular depends on which is larger on a given date. This is a Saros 126 eclipse, member 48 of 72 in that series — Saros cycles repeat roughly every 18 years, 11 days, 8 hours, producing eclipses with similar geometry at longitudes shifted about a third of the way around the globe each time. Saros 126 has been producing total eclipses since the 20th century and will continue doing so through 2044.