Can I see the aurora from my location tonight?

It depends on the Kp index and your geomagnetic latitude. Roughly, Kp 3 shows aurora in northern Norway; Kp 5 in southern Norway or Scotland; Kp 6–7 in central Europe and the northern US; Kp 8–9 as far south as central Europe or the mid-Atlantic US. Check the live Kp and 'needed Kp' figures above for your latitude.

What is the Kp index?

A 0–9 scale of global geomagnetic activity, updated every three hours. Higher Kp means the aurora oval has expanded further from the poles, making the northern (or southern) lights visible at lower latitudes.

What is Bz and why does it matter?

Bz is the north–south component of the interplanetary magnetic field carried by the solar wind. When Bz turns strongly negative (southward), it couples the solar wind's energy into Earth's magnetosphere and can dramatically boost aurora activity — often more predictive than Kp alone in the short term.

Does the solar wind speed matter?

Yes. Faster solar wind (>500 km/s) delivers more energy to Earth's magnetic field. High-speed streams from coronal holes can drive extended periods of moderate aurora activity even without a big Kp spike.

What time of night is aurora most likely?

Between about 22:00 and 02:00 local time — this is when your location is on the night side of Earth and closest to the auroral oval. Aurora can persist all night during strong storms, but 'magnetic midnight' is the statistical sweet spot.

Do I need clear skies?

Yes. Aurora happens ~100 km up in the atmosphere, well above weather clouds. Any cloud cover between you and the sky blocks it. Check tonight's cloud forecast alongside the geomagnetic data.

Which direction should I look?

In the Northern Hemisphere, look north. From high latitudes (northern Norway, Iceland, Alaska) aurora can appear overhead or even to the south. In the Southern Hemisphere, look south.

How long do auroras last?

A single 'substorm' typically lasts 20–40 minutes, but a good geomagnetic storm can produce repeated substorms across an entire night. Plan for at least an hour outside; give it time.

Can I see aurora during a Full Moon?

Yes, but brighter aurora is much more impressive under a dark sky. A bright Moon washes out the faintest structure — the pillars and dim greens — while the strongest displays remain unmistakable.

What causes the different colors?

Green is oxygen atoms at ~100 km altitude — by far the most common. Red is high-altitude oxygen (>200 km), visible in the strongest storms. Purples and blues come from nitrogen at lower altitudes.

Aurora forecast

How far the aurora oval reaches tonight depends on latitude — the geomagnetic numbers below are the same for everyone.

Can you see the aurora tonight?

Geomagnetic activity is global — the Kp index and solar wind below apply to everyone. Whether that activity reaches your sky depends on your magnetic latitude, your darkness and your cloud cover.

Global space weather · Monday 19 October

Geomagnetic activity is quiet

Planetary Kp is 0.3 — quiet conditions. Kp measures how far the auroral oval has pushed away from the magnetic poles, and it is a single global number: the same Kp applies in Tromsø, Toronto and Tasmania. It does not say the aurora is over your head.

Planetary Kp: 0.3
IMF Bz: 2.0 nT
Solar wind speed: 387 km/s
Wind density: —
Oval reach at Kp: ~65° mag. lat.

Kp, Bz, wind speed and density are properties of the Sun–Earth system, so they are safe to state for everyone. Whether the oval reaches your magnetic latitude, whether your sky is dark at the right hour and whether cloud will hide it are local questions — that is the verdict SnapCosmos produces once you set a location.

Location not set

Set a location for an aurora verdict

Kp tells you how far the auroral oval has expanded. Only your latitude tells you whether that is far enough to reach you.

The Kp level needed at your latitude
Live Kp and Bz compared against it
Whether your sky is dark enough tonight
Local cloud cover folded into the verdict

Your choice stays in this browser. Nothing is sent to a SnapCosmos server.

Recent trend

Kp over the last 24 hours

Each bar is a three-hour Kp reading. A rising trend often precedes a substorm; a sustained value above your latitude's threshold means the oval is holding at your door.

2.0

2.3

2.0

1.7

0.3

1.3

1.7

0.3

Practical

How to actually see the northern lights

Even during a strong storm, most aurora chasers see nothing — because they're in the wrong place, at the wrong time, or looking the wrong way. The fix is boring: dark, north, and patient.

Get to a dark, north-facing horizon. Light pollution and southern-facing terrain will kill your chances even during a strong storm. In the Southern Hemisphere, flip everything and face south.

Time it around magnetic midnight. Statistically, aurora is most active between 22:00 and 02:00 local time — this is when your location sits deepest on the night side of Earth.

Watch Bz, not just Kp. A negative (southward) Bz opens the door for aurora. Watch for sustained values below −5 nT — that's when a "Kp 4 night" can suddenly become a Kp 6 night.

Check the sky, not just the space weather. Aurora happens ~100 km up — well above weather clouds. Cross-reference the geomagnetic data with our Tonight page for local cloud cover, and the Moon page if you want dark-sky detail.

Trust the camera. Faint aurora can look grey to the naked eye but shows vivid green on a 3-second phone night-mode exposure. Confirm activity fast, then decide whether to stay or move.

Photographing the aurora

Match your shutter to how fast it's dancing

Aurora rewards a specific instinct: as the display gets brighter and more active, shorten your shutter — don't lengthen it. A 20-second exposure of an active corona is a smeared green blob; a 2-second exposure of the same scene shows the pillars.

Intensity	ISO	Aperture	Shutter
Faint glow (Kp 3–4)	3200	f/2.8	15–20 s
Distinct arc (Kp 5)	1600	f/2.8	8–15 s
Active bands (Kp 6)	1600	f/2.8	4–8 s
Bright, fast motion (Kp 7+)	800	f/2.8	1–4 s
Corona overhead	800	f/2	0.5–2 s

• Use a wide lens (14–24 mm) — auroral displays often fill the whole sky.
• Manual focus on a bright star with live-view at 10×. Tape the focus ring once dialled in.
• Set white balance to 3500–4000 K to keep green pure and skies neutral.
• A foreground silhouette (tree line, cabin, mountain) turns a documentation shot into a photograph.

Reference

Where the aurora shows up by Kp

A rough guide to which latitudes typically see aurora at each Kp level. Your line on this table is what determines whether tonight is 'geomagnetically interesting for you' or not.

Kp 0–2Quiet — visible only very close to the magnetic poles.
Kp 3Northern Norway, northern Alaska, Iceland.
Kp 4Central Norway, most of Iceland, central Alaska, Yukon.
Kp 5Southern Norway, Scotland, northern US border states.
Kp 6Denmark, southern Sweden, northern US (WA/MT/MN/NY/ME).
Kp 7Northern Germany, Poland, mid-latitude US (CO, KS, IL, PA).
Kp 8–9Central Europe, southern US — rare severe storms.

What it is

Where auroras actually come from

The Sun continuously blows a stream of charged particles across the solar system — the solar wind. Most of it flows past Earth, deflected by our magnetic field. But when a solar flare or coronal mass ejection (CME) sends a denser, faster burst — and when its own magnetic field points southward relative to Earth's — some of that energy is funnelled down the magnetic field lines toward the poles.

When those particles slam into oxygen and nitrogen atoms about 100 km above the ground, the atoms briefly gain energy and then release it as light: green from oxygen at 100 km, red from oxygen higher up, purples and blues from nitrogen. What you see from the ground is the shape of Earth's magnetic field made visible.

The Sun is currently near the peak of its 11-year activity cycle (Solar Cycle 25), so the coming years are unusually good for aurora hunters — even at mid-latitudes where a "quiet" year would show almost nothing.

Frequently asked questions

Keep exploring tonight's sky

Tonight's sky guide

Sunset, twilight, moonrise and darkness times for your location.

Moon tonight

Phase, illumination and rise/set times for your location.

Planets tonight

Which planets are visible after sunset and before dawn.

Milky Way tonight

When the Milky Way core is above your horizon.

Meteor showers tonight

Active showers, peak dates and effective rates for your sky.

ISS passes tonight

Live pass times with direction and altitude for your location.