Strong G3 Geomagnetic Storm (Kp 7), 10–11 October 2026: CME Hits Earth – Northern Lights in the UK?

Quick view from the OndaTravel aurora monitor (Kp over the last 24 hours, forecast peak and active NOAA alerts):

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In short: yes, there is a real chance this night, 10–11 October — but no guarantee. At G3 (Kp 7), reached on 10 October, the aurora is possible across Scotland, Northern Ireland and northern England, and often further south on camera: Kp 7 meets the thresholds below for most of the UK. NOAA expects the storm to ease to G2 (Kp 5.67) for 00:00–03:00 UTC (01:00–04:00 BST) on 11 October and then weaken further. Whether the aurora reaches the UK depends on the direction of the magnetic field inside the cloud (Bz). When Bz is negative (southward) for more than about half an hour, energy pours into the magnetosphere and the auroral oval expands south. When Bz is positive, even a very strong cloud largely passes us by. Straight after the impact, Bz swung between about −16 and +34 nT — typical of the leading edge of a CME. Follow it in the live box above or on our Northern Lights UK live radar and forecast.

When to look? For the rest of the night of 10/11 October: astronomical darkness lasts until roughly 05:10 BST on 11 October (it varies with latitude). The NOAA warning for Kp 7 or greater ran until 23:59 UTC on 10 October (00:59 BST on 11 October); the updated forecast gives Kp 5.67 (G2) for 01:00–04:00 BST and 4.67 (G1) for 04:00–07:00 BST. New Moon fell on 10 October (15:50 UTC), so there is no moonlight to wash out the sky.

Where to stand? Away from street lights, with an open view to the north: a beach, a loch or lake shore, a hilltop or open fields. Check the Met Office cloud forecast first — under full cloud cover no storm will help.

The source of all this is active region 4549 — a large sunspot group with a complex magnetic layout (beta-gamma-delta) that spent the week crossing the centre of the Sun’s disc, directly facing Earth. Below are the key events, each with its source and status.

NASA links the 10 October shock to the three clouds launched on 6 and 7 October; its models had expected further CMEs (including the one from the M6.7 flare) to arrive on Sunday, 11 October. NOAA’s updated Kp forecast (around 22:30 UTC on 10 October) no longer shows a storm on 12 October. To compare this storm with the truly big events, see our guide to the biggest aurora storms in UK history.

NOAA SWPC updated its Kp forecast around 22:30 UTC on 10 October. The storm has already been stronger than the earlier forecast: observed Kp reached 7.00 for 15:00–18:00 UTC and 6.67 for 18:00–21:00 UTC on 10 October, well above the earlier forecast of 4.67 for that evening. Updated forecast (BST = UTC + 1 hour):

The storm was driven by the arrival of several CMEs. NOAA gives a 55% chance of M-class flares (R1–R2) until 12 October, mainly from region 4549; its 3-day forecast issued at 12:30 UTC on 10 October also gave 10% for stronger flares (R3+) and 10% for an S1 radiation storm. This table is a forecast, not a promise — new bulletins appear automatically in the news feed at the top of this page.

Want to understand how NOAA builds these forecasts and why the timing can be out by several hours? We explain it in our guide to the aurora forecast tonight — how to read the live data.

Kp is calculated with a delay of a few hours, so Bz gives the earliest hint of aurora: a spacecraft at L1 sees the cloud roughly 30–60 minutes before it reaches Earth. That is why aurora watchers check Bz and Bt first and Kp second. Colour on phone photos often shows up before you can see anything with the naked eye, because the camera collects light for several seconds. If you see a bright dot or a string of lights moving across the sky, that is not the aurora: find out how to identify Starlink, satellites and other lights in the sky.

1. Clouds come first. Check the Met Office cloud forecast for the next few hours and look for gaps towards the north.
2. A dark spot with a view north. Ideally 20–30 km from a large town or city; coasts and big lochs or lakes give the lowest horizon.
3. Give your eyes 15–20 minutes. Switch off bright screens and use a red light — your eyes need time to adapt to the dark.
4. Phone: night mode and a tripod. Exposure of 3–10 seconds, focus at infinity, flash off. Further south in the UK the aurora usually looks like a pink-green glow low on the horizon in photos.
5. Camera: 15–20 mm, f/2.8, ISO 1600–3200, 5–15 seconds. Shorten the exposure when the display moves quickly.
6. Be patient. Activity comes in waves (substorms) lasting 20–40 minutes. One quiet spell does not mean the night is lost.

Stay safe: never stop on a motorway hard shoulder or a busy road verge to look up, dress warmly (October nights in Scotland and on exposed coasts can drop to a few degrees), and tell someone where you are going if you head somewhere remote.

On NOAA’s official scale, a G3 (strong) storm — the level reached on 10 October — can require voltage corrections in power grids and cause problems with satellite navigation and high-frequency (HF) radio. It is also the level at which the aurora can be seen down to around 50° geomagnetic latitude. M5+ flares (R2) cause short HF radio blackouts lasting tens of minutes on the sunlit side of Earth.

For most people in the UK, nothing changes in daily life: mobile phones, the internet and sat-nav in the car work normally. Effects may be noticed by radio amateurs, pilots on polar routes and users of high-precision GPS (for example in farming or surveying). There is no credible evidence that storms like this harm human health at ground level — the atmosphere and Earth’s magnetic field protect us from the radiation.

Region 4549 is now moving towards the western edge of the Sun’s disc. Eruptions from that part of the Sun hit Earth head-on less often, but they can still deliver a glancing blow. Over the coming days, three things matter most:

• The storm is weakening after 00:00 UTC on 11 October — NOAA forecasts G2 (Kp 5.67) for 00:00–03:00 UTC, G1 (4.67) for 03:00–06:00 UTC, then Kp 3.67–4.00 for the rest of 11 October. For 12 October no storm is forecast now (max Kp 4.33); the earlier G2 forecast for the morning of 12 October has been dropped.
• Region 4549 — NOAA gives a 55% chance of M-class flares until 12 October.
• The M6.4 flare of 10 October — a CME from it is still unconfirmed. If coronagraphs confirm an Earth-directed cloud, the forecast could change.
• The weather — even the best geomagnetic forecast is useless under total cloud cover.

We will keep adding new bulletins at the top of this page. For the bigger picture, our October 2026 guide has a daily activity log, and the best windows for the coming weeks are in our Northern Lights UK forecast for November 2026.

• NOAA SWPC — alerts, warnings and watches (K-index, sudden impulse, flares), 3-day forecast (10 Oct 2026, 12:30 UTC), forecast discussion, observed planetary Kp and Kp forecast (updated around 22:30 UTC, 10 Oct 2026).
• NOAA SWPC — real-time solar wind (SOLAR-1/SWFO-L1) and explanation of the G, R and S scales.
• NASA CCMC — DONKI: catalogue of CMEs, flares and interplanetary shocks (WSA-ENLIL models).
• Sunset, darkness and New Moon times — approximate astronomical calculations for the UK; actual times vary with latitude.

This article does not replace official bulletins. Figures from the first hours of a storm are preliminary and may change; NOAA forecasts are probabilities, not guarantees.