Forecast basis: NOAA SWPC's 27-day outlook (issued 19 Oct) and 3-day forecast (issued 24 Oct, 12:30 UTC). A one-week forecast is a planning guide, not a promise. We'll update this page when NOAA's 3-day forecast covers Halloween, around 29 October.
- Forecast: Kp 5 (G1, minor storm) on 31 October and 1 November UTC. The planetary A index of 30 is the highest in NOAA's whole 27-day outlook.
- Why: a recurring coronal hole stream. The same region caused a G2 storm on 4 October, exactly one solar rotation earlier.
- Who might see it: Scotland, southern Scandinavia, Finland, the Baltics, Canada and the northern US border states, plus anyone further north.
- The catch: a waning moon, about two-thirds lit, rises around 10–11 PM. Look early in the evening or face away from it.
- Bonus for North America: clocks go back at 2 AM on 1 November, so Halloween night is an hour longer.
What NOAA is forecasting for Halloween 2026
NOAA's Space Weather Prediction Center publishes a 27-day outlook every Monday. The latest, issued on 19 October, shows a quiet week ahead, then a clear jump at the end of the month:
| Date (UTC) | Largest Kp | Planetary A index | What it means |
|---|---|---|---|
| 27–30 Oct | 2 | 5 | Quiet. Aurora at high latitudes only. |
| 31 Oct | 5 | 30 | G1 storm. The most active day in the outlook. |
| 1 Nov | 5 | 25 | G1 storm continuing. |
| 2 Nov | 3 | 10 | Unsettled, winding down. |
Source: NOAA SWPC 27-day outlook, issued 19 October 2026. The A index measures a whole day's activity, so a high A means a long disturbance, not just one active hour.
Two storm days in a row matter here. The 31 October and 1 November UTC cover the whole of Halloween night in both Europe and North America, so whichever hours the stream peaks in, someone on the night side of Earth should be in a good position.
Why a storm is expected on Halloween
The sun spins once every 27 days or so, as seen from Earth. Coronal holes, dark regions where the sun's magnetic field opens out into space, pour out solar wind at 500–800 km/s, roughly twice the normal speed. When a coronal hole faces Earth, that fast wind hits our magnetic field a few days later. Coronal holes can last for several months, so the storms they cause often repeat every 27 days.
That's exactly the pattern this month:
- 4 October: a G2 storm, Kp 5.67, from fast solar wind, with Kp 5 again on 5 October (October forecast).
- 31 October: exactly 27 days later. NOAA expects the same region to come back around.
This is also the declining phase of Solar Cycle 25, when long-lived coronal holes become more common and recurring storms make up a bigger share of aurora nights. The background is in northern lights in 2026 and 2027.
Who might see the northern lights on Halloween?
At Kp 5, the auroral oval expands well beyond the Arctic. With clear, dark skies and a view of the northern horizon, these are realistic:
| Region | What to expect at Kp 5 |
|---|---|
| Iceland, northern Norway, Swedish and Finnish Lapland, Alaska, northern Canada | Likely overhead and active. These regions see aurora even on quiet nights. |
| Scotland, southern Norway and Sweden, southern Finland, Estonia | Good chance of a visible arc, with rays during substorms. |
| Southern Canada and US border states (Washington, Idaho, Montana, North Dakota, Minnesota, Wisconsin, Michigan, Maine) | Low on the northern horizon. Clear on camera, fainter by eye. |
| Northern England, Northern Ireland, Ireland, Denmark | Possible on camera if the storm overperforms. Look low to the north. |
| Central Europe, central US | Unlikely unless the storm reaches G2–G3. |
General guide. More detail in reading the Kp index.
If you're near the edge of the zone, use your phone. A 3–10 second exposure or night mode often shows green when your eyes see only a pale glow (here's why).
When to look: a Halloween night plan
Halloween 2026 falls on a Saturday, which helps. Here's how the night lines up:
- Dusk to about 10 PM: the darkest window. The moon hasn't risen yet. If the storm is already underway, this is your best chance for faint aurora, and it fits neatly after trick-or-treating.
- Around 10–11 PM: moonrise. The waning gibbous moon, about two-thirds lit, rises in the east. It brightens the sky but doesn't wipe out a decent display, and it lights up the landscape for photos. Face north and keep the moon behind you.
- Around midnight to 2 AM: the most likely peak. Aurora tends to be strongest within a couple of hours of local magnetic midnight (see the best time to see the northern lights).
- North America: an extra hour. Clocks go back at 2 AM on 1 November, so the 1–2 AM hour happens twice.
How confident is this forecast?
Moderately. Forecasts based on recurring coronal holes are among the more reliable long-range space weather predictions, because the source has already shown what it can do. But coronal holes change shape and strength from one rotation to the next. This month shows both sides: NOAA's outlook called for Kp 5 on 21–22 October from another recurring stream, and the real peak was Kp 4.67, close but just short of storm level.
There's also an unknown in our favor. The sun is still producing flares and coronal mass ejections, and nothing that erupts in the next few days is in this forecast yet. A CME arriving on top of a coronal hole stream is how modest forecasts turn into surprise storms.
The best plan: keep Halloween evening free if you're in the zone, check NOAA's 3-day forecast from 29 October, and decide on the night using live data.
The 2003 Halloween storms: the night the aurora reached Texas
Halloween has form. Between late October and early November 2003, during the declining phase of Solar Cycle 23, a group of huge sunspots unleashed some of the most powerful solar activity ever recorded:
- Massive flares. On 28 October an X17 flare launched a coronal mass ejection that reached Earth in about 19 hours, far faster than the usual two to three days. On 4 November came the largest flare of the satellite era. It overloaded the GOES X-ray sensors at X28, and later estimates put it at around X40 to X45.
- An extreme storm. On 29–30 October, the geomagnetic storm reached G5, the top of NOAA's scale, with Kp 9.
- Aurora far to the south. The northern lights were seen as far south as Texas and Florida in the US, and from countries around the Mediterranean.
- Real-world effects. A power outage hit Malmö in southern Sweden, twelve transformers were damaged in South Africa, airlines were advised to avoid high polar routes, astronauts on the ISS moved to better-shielded modules, and several satellites were damaged or put into safe mode.
Nothing like that is forecast for this Halloween. A G1 storm is minor, safe and, for aurora watchers, simply good news. But 2003 is a reminder that the years after a solar maximum, like now, are when some of the biggest storms tend to arrive. Our G3 storm on 10 October was a recent example.
Frequently asked questions
Will the northern lights be visible on Halloween 2026?
Possibly. NOAA forecasts Kp 5, a G1 storm, on 31 October and 1 November. If it arrives, aurora could be seen from Scotland, southern Scandinavia, Canada and the northern US, given clear, dark skies.
What time should I look on Halloween?
Early evening, before the moon rises around 10–11 PM, gives the darkest sky. The aurora is usually strongest around local midnight, so check again then.
Why does NOAA expect a storm on Halloween?
A coronal hole caused a G2 storm on 4 October. The sun rotates every 27 days, so the same region faces Earth again on 31 October.
What were the 2003 Halloween solar storms?
A series of powerful flares and coronal mass ejections that caused a G5 storm on 29–30 October 2003, with aurora seen as far south as Texas and the Mediterranean.
References
- NOAA Space Weather Prediction Center, 27-day outlook, issued 2026-10-19.
- NOAA SWPC, 3-day forecast, issued 2026-10-24 12:30 UTC.
- NOAA SWPC, Daily geomagnetic indices (observed Kp, October 2026).
- Forbes, Northern lights forecast: 12 states may see aurora, 3 October 2026.
- Wikipedia, 2003 Halloween solar storms.
- NASA Scientific Visualization Studio, Looking back at 2003's spooky Halloween solar storms.
- NOAA NCEI, Remembering the great Halloween solar storms.
- Catalina Sky Survey / University of Arizona, Moon phases, October 2026.
Free printable guide. Take it with you: The Aurora Night Guide (PDF, 3 pages) covers the Kp index, when to go, a packing checklist and phone camera settings.