You can see the aurora tonight when three things line up: the auroral oval has moved close enough to where you live, your sky is dark and clear towards the nearest magnetic pole, and you look while the activity lasts. All three can be checked from home in a few minutes, wherever you are on Earth.
Your geomagnetic latitude matters more than your map latitude
Aurora gathers in a ring around each geomagnetic pole, not around the geographic poles. The magnetic poles sit away from the geographic ones, so two towns on the same parallel can have quite different chances. NOAA’s Space Weather Prediction Center states its aurora rule of thumb in geomagnetic latitude for this reason (NOAA SWPC, Tips on viewing the aurora).
The southern lights follow the same physics. The aurora australis forms its own oval around the southern geomagnetic pole, and NOAA’s aurora forecast shows it on a separate hemisphere map (NOAA SWPC, Aurora 30-minute forecast). Everything below applies in both hemispheres; only the direction you face changes.
How Kp moves the oval towards you
Kp measures how strongly Earth’s magnetic field is being disturbed. The German Research Centre for Geosciences (GFZ) calculates it for every three-hour interval from 13 geomagnetic observatories around the globe (GFZ, Kp index), and the scale runs from 0 to 9 (NOAA SWPC).
When Kp rises, the oval’s edge moves away from the pole. NOAA gives a simple average: at Kp 0 the equatorward edge lies at about 66° geomagnetic latitude, and it moves roughly 2° for each step of Kp, reaching about 48° at Kp 9. These are averages (NOAA SWPC). NOAA’s storm scale lists where aurora has actually been seen at each level (NOAA Space Weather Scales).
| Kp | NOAA storm level | Equatorward edge of the oval (geomagnetic latitude) | Where NOAA says aurora has been seen |
|---|---|---|---|
| 0 | none | about 66° | far towards the pole, dim |
| 3 | none | about 60° | moving away from the pole and brightening |
| 5 | G1 minor | about 56° | commonly at high latitudes, such as northern Michigan and Maine |
| 6 | G2 moderate | about 54° | as low as New York and Idaho, typically 55° |
| 7 | G3 strong | about 52° | as low as Illinois and Oregon, typically 50° |
| 8 | G4 severe | about 50° | as low as Alabama and northern California, typically 45° |
| 9 | G5 extreme | about 48° | as low as Florida and southern Texas, typically 40° |
The right-hand column reaches lower latitudes than the oval itself because aurora glows high in the atmosphere. When it is bright, you can see it from as far as 1000 km away, low over your poleward horizon (NOAA SWPC, Aurora 30-minute forecast).
What this looks like in different parts of the world
North America. Canada’s space weather service places most of the country in two bands: the auroral zone between 63° and 77° magnetic latitude, where aurora is seen most often, and the sub-auroral zone between 49° and 63° (Space Weather Canada, glossary). Strong activity brings the lights to southern Canada, as near Montreal (Canadian Space Agency). For the United States, see NOAA’s examples in the table.
Northern Europe. In northern Finnish Lapland, three clear nights out of four have aurora; in Sodankylä it is every second night, and in Helsinki about one night a month (Finnish Meteorological Institute). In the far north of Scotland a display is possible every few months (British Geological Survey). Moderate storms around Kp 6 to 7 usually bring the oval only to southern Iceland or the Faroes, and it takes Kp 8 to 9 to move it over the UK itself, which is very rare (Met Office).
Central Europe. Further south, sightings need exceptional storms. On 10 May 2024 people across Switzerland saw aurora with the naked eye, even from cities; the following night, near Bern, the faint glow showed up only in photographs (University of Bern, AIUB).
East Asia. On 1 December 2023, a bright red aurora was seen with the naked eye from Hokkaido in Japan, although the magnetic storm was not large. Researchers traced it to unusually dense solar wind (University of Tokyo), so a modest Kp does not always rule out a display.
Southern Hemisphere. In Australia the aurora australis is best seen from Tasmania and the southern coastlines of the mainland (Bureau of Meteorology); on rare occasions it has reached as far north as southern Queensland (BoM Space Weather Services). In New Zealand, the University of Otago recommends dark beaches on the east coast of the southern South Island, such as those around Dunedin, facing south (University of Otago Aurora Alert).
Reading Kp, the oval map and Bz together
Kp tells you whether the evening is promising. Check whether a number is a forecast for an interval still to come or an estimate based on measurements already in. Times are given in UTC, so convert them to your own clock before planning (NOAA SWPC, Planetary K-index; GFZ).
The oval map tells you when to look. NOAA’s OVATION model uses the solar wind speed and magnetic field measured at the L1 point, upstream of Earth, to forecast where aurora will be 30 to 90 minutes ahead. Pick your hemisphere and read the valid time on the image. The oval is green and turns red where the model expects stronger aurora; that shading is not the colour you will see. If the solar wind data drop out, NOAA drives the model from the current Kp instead, and the forecast then has no lead time (NOAA SWPC, Aurora 30-minute forecast).
Bz tells you whether energy is getting in. On NOAA’s solar wind plot, Bz is the north–south part of the magnetic field carried by the solar wind, shown in nanotesla; values below zero point south (NOAA SWPC, Real-time solar wind). A southward field is the most important condition for passing energy from the solar wind into Earth’s magnetosphere, and strong storms build when it stays southward for several hours or longer (NOAA SWPC, Geomagnetic storms). A brief dip promises little.
Darkness, cloud and the Moon decide the rest
Aurora is only visible when the sky is dark. The best hours are usually within an hour or two of local midnight, roughly 10 pm to 2 am, and the window widens towards evening and morning when activity is high (NOAA SWPC). Near the poles, summer nights are too light; Finland’s best months are February to March and September to October (Finnish Meteorological Institute).
A full Moon lowers how bright the aurora appears to you, though not how bright it actually is, and city lights do the same (NOAA SWPC). Cloud low on the horizon matters most, because that is where a distant display appears (University of Otago). Face the nearest pole: north in the Northern Hemisphere, south in the Southern. If the oval is right above you, aurora can appear anywhere in the sky, so look all around (Canadian Space Agency).
Why your camera sees more than your eyes
A camera is more sensitive than the human eye and picks up the colour of the aurora; a faint display can look white or grey to you (British Geological Survey). Long exposures gather light over seconds (Met Office); the Swiss photographs of May 2024 used 2.5-second exposures and show colours more vivid than observers saw (University of Bern, AIUB). The University of Otago rates weak activity as visible to a camera only and strong activity as clearly visible by eye (University of Otago).
So a pink picture in the family chat does not mean everyone outside saw pink. Note what your eyes saw before you check the photo, and keep both.
A three-step check for tonight
- Look out first. Is it dark yet, and can you see stars low towards the pole, north or south?
- Check the space side. Open NOAA’s oval map for your hemisphere, read its valid time, and check Kp. Is the oval near your geomagnetic latitude, and has Bz stayed southward for a while?
- Go out, then wait. Pick a spot without lights towards the pole, give your eyes time to adjust, look first and photograph second.
Sources
- NOAA SWPC, Tips on viewing the aurora: https://www.spaceweather.gov/content/tips-viewing-aurora (Kp 0 to 9; edge about 66° at Kp 0, about 2° per Kp step, 48° at Kp 9; geomagnetic not geographic; approximate averages; 10 pm to 2 am; full Moon; dark needed)
- NOAA SWPC, Aurora 30-minute forecast (OVATION): https://www.spaceweather.gov/products/aurora-30-minute-forecast (30 to 90 min lead; L1 input; Kp fallback without lead time; green to red; visible up to 1000 km away)
- NOAA Space Weather Scales: https://www.spaceweather.gov/noaa-scales-explanation (G1 to G5 with Kp 5 to 9; places and typical 55°, 50°, 45°, 40° geomagnetic latitude)
- NOAA SWPC, Geomagnetic storms: https://www.spaceweather.gov/phenomena/geomagnetic-storms (southward field; several to many hours)
- NOAA SWPC, Real-time solar wind: https://www.spaceweather.gov/products/real-time-solar-wind (Bz GSM in nT; shading below 0 nT)
- NOAA SWPC, Planetary K-index: https://www.spaceweather.gov/products/planetary-k-index (estimated 3-hour Kp from magnetometers; mean of 13 observatories; forecast on separate page)
- NOAA SWPC, Coronal mass ejections: https://www.spaceweather.gov/phenomena/coronal-mass-ejections (fastest about 15 to 18 h, slower several days; used for figure B, not quoted in text)
- GFZ Potsdam, Kp index: https://kp.gfz.de/en/ (three-hourly; 13 observatories)
- Space Weather Canada, glossary: https://www.spaceweather.gc.ca/info-gen/glossa-en.php (auroral zone 63° to 77°, sub-auroral 49° to 63° magnetic latitude, Canadian territory)
- Canadian Space Agency, Aurora viewing tips: https://www.asc-csa.gc.ca/eng/astronomy/northern-lights/aurora-viewing-tips.asp (southernmost Canada; Boucherville near Montreal; anywhere in the sky)
- Finnish Meteorological Institute, Northern lights: https://en.ilmatieteenlaitos.fi/northern-lights (3 of 4, 1 of 2, about 1 per month; 9 pm to 1 am; best months)
- British Geological Survey, Viewing aurora: https://geomag.bgs.ac.uk/education/viewing_aurora.html (far north of Scotland every few months; camera more sensitive)
- Met Office, Auroras: https://weather.metoffice.gov.uk/learn-about/space-weather/auroras (Kp 6 to 7 southern Iceland or Faroes; Kp 8 to 9 over UK, very rare; long exposures)
- University of Bern, AIUB, Space weather events May 2024: https://www.aiub.unibe.ch/research/space_weather/space_weather_events_may_2024/index_eng.html (naked eye in cities 10 May; 2.5 s exposures; second night only in pictures)
- University of Tokyo, Hokkaido aurora: https://www.eps.s.u-tokyo.ac.jp/?p=14112 (1 Dec 2023; red; weak storm; dense solar wind; 400 to 600 km)
- Bureau of Meteorology, Catching the aurora: https://media.bom.gov.au/social/blog/1870/catching-the-aurora/ (Tasmania and southern mainland coasts; view south; avoid bright Moon)
- BoM Space Weather Services, Facts about the aurora: https://www.sws.bom.gov.au/Educational/1/1/7 (rarely as far north as southern Queensland)
- University of Otago, Aurora Alert: https://auroraalert.otago.ac.nz/aurora (south-east coast of South Island, Dunedin; view south; camera vs eye levels; horizon cloud)