Aurora forecast & alerts · iOS 17
Should you go outside tonight?
That is the only question an aurora app needs to answer, and almost none of them do. They show you a Kp number and a coloured map of the planet, and leave you to work out what it means for the sky above your head.
- One payment, never a subscription
- No account
- No ads, no tracking
- Public data, cited on screen
Tromsø · 21:40
Go now
Aurora overhead
32% chance at your latitude · Kp 5
Clear skies
12% cloud cover
Dark enough
Sun is 17° below the horizon
Bright moon
78% lit — faint aurora will wash out
How it decides
Three things, in this order
Blika applies them the way you would if you had the data in front of you, and it tells you which one was binding. A verdict you can argue with is worth more than a score you cannot.
Aurora activity
NOAA's OVATION model, read at your grid square rather than a national average. A storm over Iceland is not a storm over you.
Cloud cover
The factor most aurora apps leave out entirely, and the one that ruins most chases. A 90% aurora probability under thick overcast is a wasted drive at two in the morning, and Blika will say so.
Darkness
The sun has to be far enough below the horizon. In summer, at high latitude, it often simply is not — and an app that alerts you anyway is wasting your attention.
And the moon, as a modifier
Bright moonlight will not stop you seeing a strong display, but it will wash out a faint one. So it is flagged, never used to veto — you deserve to know before you drive.
The answer
Three verdicts, never a score out of 100
A number invites you to argue with it. A verdict tells you which factor is the binding one — and that is the thing that actually changes your evening.
Go now
All three factors are on your side. Coat, keys, door.
Keep an eye out
One factor is marginal — thin cloud, or activity that has not quite arrived. Worth checking again in an hour.
Not tonight
Something is decisively against it, and Blika names which one so you can decide whether to believe it.
The dashboard
Eight widgets. You pick which, and in what order.
The chaser who watches Bz and the photographer who watches the moon should not be handed the same screen. Every card answers one question and shows the number it rests on — none of them shows a composite score, because the verdict above the grid is the only place Blika is allowed to combine things.
The verdict and its three reasons are free. The dashboard is what the one-time purchase unlocks.
Aurora overhead
NOAA's OVATION probability at your 1° grid square, not a national average.
Kp index
The planetary index everyone quotes. Context, never the verdict.
Cloud cover
The factor that ruins most chases, for the hour in question.
Moon
Illumination and phase. A bright moon washes out a faint display.
Tonight's window
The stretch tonight when it is both dark enough and clear enough.
Solar wind
Speed and Bz from DSCOVR. Bz pointing south is what opens the door.
Darkness
Sun elevation across the night, with the twilight bands marked.
Next three nights
Which are clear and dark. Aurora is not forecast this far out.
Pricing
One payment. Not a subscription.
Most aurora and weather apps in this category bill by the week. Blika asks once.
The verdict and its three reasons are free, forever, with no account and no ads. A single one-time purchase unlocks the dashboard, and that is the only thing Blika will ever charge you for.
There is no server behind this app and no account to run. The data is public and free. Charging rent for arithmetic over public feeds would be the pricing equivalent of dressing a guess up as a percentage.
Honest by design
What Blika will not do
Tell you it is good when it is not
When it says “Not tonight”, it names the reason — too bright, overcast, quiet sky — so you can decide for yourself whether to trust it.
Alert you about the other side of the planet
A number crossing a threshold somewhere else is not a reason to put your coat on. Blika reads the grid square you are standing in.
Forecast aurora days ahead
Nobody can, so Blika does not pretend to. The three-night outlook covers cloud and darkness — the two things that genuinely are forecast that far — and says so on its face.
Blika also tells you when a reading is stale rather than quietly showing you yesterday's sky. If one of the three load-bearing factors cannot be fetched, there is no verdict and the app says which one is missing.
Where the numbers come from
All of it is public, and none of it is ours
Sources are shown on screen in the app, and listed here so you can check them before you install anything.
| Source | What it gives | Note |
|---|---|---|
| NOAA OVATION | Aurora probability on a 1°×1° global grid | Downloaded whole and indexed on your iPhone, so NOAA is never told where you are |
| NOAA planetary Kp | The planetary K index | Shown as context on one card. It is never the verdict |
| NOAA DSCOVR | Solar wind speed, density and Bz at L1 | Bz pointing south is what opens the door to a display |
| Open-Meteo | Hourly cloud cover, four days ahead | The only request that carries your approximate coordinates |
| Your device | Sun elevation, moon phase, tonight's window, the outlook | Computed locally from your location and the clock. No API, no network |
Before you install
Questions
Do I need to be in the Arctic for this to be useful?
No, but latitude is the single biggest thing working for or against you. Blika reads the aurora probability at your own grid square, so it will tell you honestly that the answer where you are is “not tonight” far more often than it is “go now”. That is the point — it saves you the checking rather than manufacturing excitement.
During a strong storm the oval pushes a long way south, and that is exactly the night you want an app that is watching your square rather than a national headline.
Why does it need my location?
Because every one of the three factors is local. The aurora probability is read at your 1°×1° grid cell, the cloud cover is the cloud above you, and the sun's elevation depends on where you are standing.
Location is requested at kilometre accuracy, and the only request that carries it leaves for Open-Meteo to ask about cloud. Full detail on the privacy page.
Is there a free version?
The free app is complete in the sense that matters: tonight's verdict for where you are, on demand, unlimited, with the three reasons behind it. No account, no ads, no trial timer.
The one-time purchase adds the dashboard — the eight widgets, solar wind and Bz, tonight's window and the three-night outlook.
Does it send push alerts?
Not yet. It is the next thing on the list, and it is being built carefully for the reason the rest of the app exists: an alert that fires because a number crossed a threshold on the other side of the planet trains you to ignore it.
Why not just show me the Kp index?
Kp is a planetary average, published in three-hour blocks, and it says nothing about whether there is cloud over your head or whether the sun has set. It is real and it is useful, which is why it is on a card of its own — as context, never as the verdict.
Who makes it?
One person. If it gets something wrong, the reasons are on the screen — tell me which one was off, at support@blika.app.
Stop guessing at midnight
Open it, read the answer, close it. On a good night you will be outside in under ten seconds, which is where you actually want to be.
iOS 17 or later. Should you go outside tonight?