Aurora forecast · iOS and Android
Will you see the aurora tonight?
One plain-language answer for exactly where you are standing.
Aurora forecast · iOS and Android
One plain-language answer for exactly where you are standing.
A Kp 7 is worth nothing when its cloudy, the moon is full, or it's 9pm in June.
Heliocast weighs all four for your coordinates and gives you one answer, plus the reason when the answer is no.
Two questions a forecast has to answer once you actually plan around it: which night is worth the drive, and when should something wake you.
Every night scored and ranked, with the dark hours and the moon behind each score. Three nights free, fourteen with Pro.
Kp tells you the aurora is already happening, which is too late to drive anywhere. Heliocast also watches the solar wind a million and a half kilometres upstream and wakes you when the magnetic field turns south, usually an hour or more before anything reaches the sky. It holds the alert if your sky is clouded over or the sun is still up, app closed or not.
None of this is our guess about the sky.
The same public instruments professional space-weather forecasters watch. Fetched by our server, so the agencies never see anything about you.
Every active region on the disk, numbered and tracked, straight from NASA's Solar Dynamics Observatory. When one of them fires, you find out where it was pointing and when the cloud arrives.
One plan, once a year. No monthly tier and no trial countdown, because the free tier is the trial.
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Heliocast Pro
$4.99
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That depends on four things at once, which is exactly why Heliocast exists. You need geomagnetic activity strong enough to push the auroral oval over your latitude, a sky dark enough to see it against, a moon that is not washing it out, and no cloud in the way. Heliocast checks all four for your coordinates and gives you a single answer, plus the reason when the answer is no.
Kp is a 0-9 scale of global geomagnetic disturbance, published by NOAA every three hours. Roughly: the higher the Kp, the further from the poles the aurora is visible. At Kp 0 the auroral oval sits near 66.5° magnetic latitude; by Kp 9 it has pushed down to about 48°. It is the single most quoted aurora number, but on its own it never tells you whether you will see anything.
No. Heliocast works anywhere on Earth, in both hemispheres - the same model handles the aurora australis in Tasmania, New Zealand and southern Chile. During a strong geomagnetic storm the oval reaches well into the mid-latitudes, and the alerts exist precisely so you find out on the nights it does.
Yes. Our server watches NOAA's 1-minute feed all night and sends a push the moment your threshold is crossed, whether or not Heliocast is running. One overnight alert is free.
Before, on the alert that matters. The Kp index is a three-hour average, so an alert built on it reaches you once the display is already running and often once it is over. Heliocast also reads the solar wind from spacecraft a million and a half kilometres sunward of Earth, where a southward turn in the magnetic field is visible well before the energy it carries arrives - usually an hour or more of warning, which is the difference between reading about it and driving somewhere dark for it.
$4.99 per year - one plan, no monthly option and no free trial, because the free tier already is the trial. It renews yearly and you can cancel any time from your App Store or Google Play account.
The aurora is out there.