Features

Aurora alerts

Updated 2026-10-25

The aurora is the one thing in the night sky you cannot put in a diary. The sun, the moon and the Milky Way core run to a timetable you can plan a year out. A geomagnetic storm gives you a few hours’ warning, and a substorm can begin and end inside ninety minutes — so the question is never “will there be an aurora next Tuesday”. It’s “should I get in the car right now?”

Viewpoint answers that in two parts: whether the lights can reach a place at all, and whether they are happening tonight.

Can the aurora reach this spot?

This is the question that decides everything else, and it is the one most often got wrong — because the latitude that matters is not the one on the map.

The aurora forms in ovals around the Earth’s magnetic poles, and those sit a long way from the geographic ones. So two places on nearly the same map latitude are not remotely equal: a big storm reaches Chicago, and a storm on the same scale does not reach Madrid, which is barely further south. What decides it is your geomagnetic latitude.

Open a saved spot and Viewpoint gives you a verdict for that exact place:

  • How often the oval can realistically get there — often, occasionally, or only in the rare big storms.
  • The lowest Kp it takes. “Reaches here at Kp 3” and “reaches here at Kp 7” are very different invitations: one is a few nights a season, the other is a handful across a solar cycle.

A few places sit right on the edge of what the model can resolve. Those are marked uncertain rather than handed a confident number — we would rather say “we can’t promise this one” than guess.

This verdict is about geography, not tonight. It doesn’t move with the weather, the moon or the solar wind, and it reads the same in July as in January.

Where the model is least certain

The geomagnetic model is a good description of the Earth’s field, not a perfect one, and it is weakest in the far south — the sector covering Australia, New Zealand and southern South America. If you are shooting the aurora australis from somewhere like New Zealand or Patagonia, treat a quiet verdict there as the model’s best guess rather than the last word, and check a regional aurora forecast as well. The southern lights are genuinely photographed from those places.

Tonight: the facts

Where the aurora can reach, the aurora tile on the Conditions page and the aurora card on a spot lead with facts, in the same order every time, and never with a verdict. Viewpoint tells you what is happening and what your place needs; the decision to go is yours.

  • Activity. The Kp measured now, with how old the reading is, and the highest Kp forecast for tonight. If the feed is stale or unreachable, it says so and gives the age. It will never show you a confident “Kp 0” it does not actually have — a made-up calm sky is worse than an honest blank.
  • What your place needs. The lowest Kp that reaches it (“Amsterdam needs Kp 7”). Where aurora is usually faint to the eye at that latitude, a line says your camera may catch what you cannot see.
  • The dark window. When the sky is dark enough at that place, in the place’s own time zone, not yours. Plan a trip to Iceland from Amsterdam and the times you read are Icelandic. Where the sun never sets, it says midnight sun until a date; where it sets but never gets dark, it says no dark window until a date.
  • The moon. Its phase, and how long it is up.
  • Cloud. The forecast cloud for the dark window, and when it clears.

Tap the tile for the full aurora sheet: the three-day Kp history and forecast, the solar wind, and a globe of NOAA’s aurora probability map for your place’s hemisphere, with your place marked. The map is NOAA’s own model, the OVATION forecast of where the aurora oval sits for roughly the next half hour; its edge is the 10 % probability line, and the sheet tells you how old the map is.

The dark window uses nautical night — the sun more than 12° below the horizon — rather than the astronomical night (18°) the Milky Way needs. That is deliberate: an aurora is far brighter than the galactic core, and waiting for astronomical darkness would write off the first hour of a substorm at almost every mid-latitude spot. For shooting a faint display against a truly black sky, astronomical night is still the better target.

The alerts

The facts tell you whether a place is worth watching. The alerts are what actually get you out of the house. Tap the bell on a place’s page in Conditions and the alerts sheet slides up. It shows each condition on or off, aurora among them, and the forecast area around the place: This spot, Nearby or Wide. Switch aurora on, tap Turn on alerts, and Viewpoint watches that place for you. The same sheet opens when you add a new place, once, and Skip keeps the place without alerts. The other conditions on the sheet are set the same way, and turning aurora off leaves them as they are.

Aurora alerts reach you in two forms: the live alert, which is its own notification, and the heads-up, which is part of the place’s briefing.

The live alert

When the aurora is active over that place, you hear about it inside the window when there is still time to drive — not in tomorrow morning’s summary.

Before it sends anything it checks three things together:

  • The Kp has reached that place’s own threshold — the one from the reach verdict above, not a global number.
  • It is dark there.
  • The cloud is thin enough to see through.

All three, or it stays quiet. And it is quiet by design: you get one alert per onset, not a stream while a storm runs. If the sky goes quiet and flares up again a good while later, that is a new event and you hear about it again.

The alert states facts, not a verdict. Its title says what is reaching which place (“Aurora reaching Amsterdam · Kp 7”). Its body says what the place needs first, then up to three more facts, such as which way to face (a compass direction toward the nearest edge of the aurora oval, and only when you are outside it), when cloud returns, whether the moon is up, and how long it stays dark. The text is in your language and the times are in the place’s own time zone.

The heads-up

The heads-up is the afternoon version: when the forecast first reaches your place’s threshold during tonight’s dark window, the aurora appears as one item in that place’s briefing, a few hours ahead, so you can plan the trip. The item says “forecast”, states the span of hours, the Kp forecast and what the place needs, then cloud and moon. Tap the briefing and the aurora sheet for that place opens at that hour.

  • A briefing is sent only when the outlook changed. If nothing worth saying changed since the last one, nothing is sent.
  • It is only sent while it still holds: if the forecast no longer reaches your place when the time comes, or the reading is stale, the aurora item is left out.
  • It is not sent where there is no dark window tonight, such as under the midnight sun.
  • The live alert fires whether or not a heads-up was sent.

Notification permission is asked the first time you arm an alert. Aurora alerts are part of Online. See Getting started for the full plan breakdown.

What it can’t tell you

Being straight about the edges of this matters more here than almost anywhere else in the app:

  • It does not forecast solar activity. It reads the live measurement. For “what is the sun likely to do over the next few days”, use a dedicated space-weather or aurora forecast — that is a different discipline and we don’t pretend to it.
  • Cloud is a forecast, not a fact. The sky over your spot is the one thing that can quietly ruin an otherwise perfect night.
  • It cannot see the display. “Reaches here” is a statement about what is possible, never a promise that something is in the sky right now.

Where to find it

  • iPhone and Android — the aurora tile on a place’s page in Conditions, and the aurora sheet it opens. It leads with the facts above, carries the bell that opens the alerts sheet, and opens the same sheet the alerts land on. On a spot, the aurora card says the same about that exact place. The same card also sits at the top of Notifications, for where you are right now or any place you pick.
  • Web app — the aurora card on a spot, with the reach verdict, tonight’s Kp and the dark window, and the bell.

Where the oval genuinely cannot reach a place, no aurora tile appears at all, rather than an empty one holding out false hope.

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