TonightAurora
Tonight · — · Ushuaia, Argentina

Aurora tonight in Ushuaia

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Crunching NOAA Kp, cloud cover, moon phase and darkness for Ushuaia…

connecting to NOAA SWPC + Open-Meteo…

Can you see the aurora australis from Ushuaia?

The southern lights sit over the magnetic pole the same way the northern lights do, which means Ushuaia looks south for them — and is subject to exactly the same Kp index that aurora watchers in the Arctic follow.

Ushuaia needs Kp 5 and is the southernmost city in the world, which makes it the closest inhabited place to the southern auroral oval. The threshold is low for a city of its size, and the surrounding mountains and Beagle Channel give you both darkness and an open southern horizon without leaving town for long.

Country
Argentina
Magnetic latitude
-54.8°S
Geographic latitude
54.80°
Aurora threshold
Kp 5
Light pollution
Bortle 4
Deep-dark nights / yr
277
Sun at solar midnight
58.6° below horizon
Midnight sun
none

When to look: the Ushuaia aurora season

Counted properly, Ushuaia gets 277 nights of astronomical darkness a year. They begin around **4 Feb** and end about **7 Nov**, and inside that window the sky is dark enough that the only things standing between you and a display are cloud and geomagnetic activity. The counter-season is just as clearly defined: from about **8 Nov** to **3 Feb** (88 nights) the sun never gets 18° below the horizon, so the sky never reaches full darkness, and between roughly 5 Dec and 6 Jan it does not get properly dark at all — no display, however strong, is visible in that stretch.

The sun reaches 58.6° below the horizon at Ushuaia on the darkest night of the year, and the nights stay dark enough for aurora watching year-round — the practical constraint here is weather and geomagnetic activity, not daylight.

Where to go in Ushuaia

The Beagle Channel shoreline is the natural choice: water to the south, mountains behind you, and very little artificial light between you and the aurora.

The aurora sits over the magnetic pole, so from Ushuaia you are looking toward magnetic south — which in practice means a spot with an open horizon in that direction and no streetlight in front of you. The "best window" in tonight's answer marks the first hour where cloud cover drops below roughly 40% while the sky is properly dark at this latitude.

What Kp do you need in Ushuaia?

Kp is a planetary number, and the only way to read it usefully is against this city's own threshold. For Ushuaia that threshold is Kp 5, set by a magnetic latitude of -54.8°:

Kp indexWhat to expect at Ushuaia
Kp 0Nothing from Ushuaia — the oval stays too far south. On those nights the forecast at the top of this page will say NO, and that is the honest answer.
Kp 1Nothing from Ushuaia — the oval stays too far south. Nothing to plan around — save the trip for a stronger forecast.
Kp 2Not visible here. On these nights a trip south would be the only option. Worth knowing so that a quiet night reads as expected rather than disappointing.
Kp 3Faint glow on the southern horizon, and only from genuinely dark ground outside the city. Check the cloud forecast before committing to the drive.
Kp 4Marginal: expect at most a dull arc low in the south, and only away from town. Give your eyes 20 minutes to adapt before deciding it is a no.
Kp 5This is the threshold night — a clear sky puts a pale green arc over the southern horizon, brighter during substorms. A clear sky is the deciding factor at this level.
Kp 6Strong showing — tall rays, obvious colour, and curtains that reach well above the horizon. Get out early — the best structure often arrives in the first hour.
Kp 7Everything you came for. Overhead curtains, rapid movement, and colour visible without a camera. These are the nights people travel for.
Kp 8Exceptional event (G4–G5). At this level the display can fill the whole sky above Ushuaia, not just the southern horizon. Watch the live forecast through the evening; this level can build quickly.
Kp 9Exceptional event (G4–G5). At this level the display can fill the whole sky above Ushuaia, not just the southern horizon. Find a wide-open horizon — at this level the display can move overhead.

Two things have to line up for Ushuaia: the planetary index has to reach about Kp 5, and the local sky has to be clear. Kp is a three-hour planetary average, so a display can start and fade inside one interval, and short substorm bursts routinely outperform the headline number. When the answer above says MAYBE, that usually means the geomagnetic side is fine and cloud is the question.

How tonight's answer is calculated for Ushuaia

The score above is built from five weighted factors, each using Ushuaia's own figures rather than a regional default: Kp against a local threshold of 5 (35%), cloud cover averaged across the dark hours at -54.80°, -68.30° (25%), moon illumination (15%), this latitude's astronomical darkness window (15%) and Bortle 4 light pollution (10%). The scoring method, its inputs and its failure modes are written up in full on our methodology page. No account, no app, no email address — everything above is computed in your browser from NOAA and Open-Meteo data. Anonymous analytics and Google's advertising script are the only third parties involved, both explained on the privacy page.

Ushuaia aurora — quick answers

What Kp do you need to see the aurora in Ushuaia?

The number that matters here is Kp 5, the point at which the oval reaches Ushuaia's magnetic latitude of -54.8°. Treat it as the start of the window rather than the peak: the display gains height and structure as the index climbs, and this is the level the verdict above is measured against.

How accurate is tonight's aurora forecast for Ushuaia?

The verdict is a weighted composite of five measurements rather than a guess: NOAA's Kp forecast (reliable to roughly 12 hours), cloud cover through the night at Ushuaia's coordinates from Open-Meteo, moon illumination, the dark window computed for this latitude, and Bortle 4 light pollution. Cloud decides more nights than any other input, which is why the page returns LOW or MAYBE far more often than a hopeful GO.

How dark does it actually get in Ushuaia?

277 nights a year reach full astronomical darkness here, with the sun dropping to 58.6° at its lowest. The other nights are the trade-off: around 8 Nov to 3 Feb, the sun stays too high for a true black sky.

Can you see the aurora from Ushuaia city centre?

Only when the display is strong. Bortle 4 means the city's own light is competing with the aurora, and at Kp 5 it usually wins from the centre. Give yourself 20–40 minutes of driving and the same night looks substantially better.

When is the best time to see the aurora australis in Ushuaia?

Astronomical darkness runs from about 4 Feb to about 7 Nov. Between roughly 8 Nov and 3 Feb the sun never gets 18° below the horizon, so the sky never reaches full darkness — our engine returns NO during that stretch instead of pretending otherwise. Within any dark night, 21:00–01:00 local is the most active window.

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