Aurora Alerts: Kp & Forecast
Kp index, dark hours & NOAA
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
The aurora only shows up when everything lines up: enough magnetic activity, a sky that is dark enough, and no clouds in the way. This app tells you plainly how things look where you actually are – not as a global number, but as a judgement for the spot you are standing on.
NOW
• A clear answer: very low, low, moderate or high chance
• Probability from NOAA's OVATION model for your own coordinates
• Kp index, solar wind speed and Bz
• A short reason for why the answer came out the way it did
TONIGHT AND THREE DAYS AHEAD
• The Kp forecast as bars, with the hours of darkness drawn into the same picture
• The best three-hour slots: when it is dark and Kp is at its highest
• One line per night: when darkness starts and ends, and the night's peak Kp
MAP
• The auroral oval around the pole, with your own position marked
• The daylight side is dimmed – you will not see aurora there even when it is present
• Northern and southern hemisphere
ALERTS
• Pick the threshold yourself: Kp 3, 4, 5 or 6
• You only get an alert when the threshold is crossed and it is dark where you are
• iOS decides how often the app may wake in the background, so an alert can arrive late or not at all. If the night matters, check the forecast yourself as well.
LOCATION
• Device location, or a place you choose by hand
• A ready list of spots: Tromsø, Abisko, Kiruna, Rovaniemi, Kilpisjärvi, Reykjavík, Akureyri, Fairbanks, Yellowknife, Churchill, Hobart and more
• You can also type in coordinates yourself
• The app works fully even if you never grant location access
GUIDE
• What Kp, Bz, solar wind and magnetic latitude actually mean
• What makes a good night
HONESTLY
This is a forecast, not a promise. It is built on open data from the NOAA Space Weather Prediction Center and on a solar elevation calculation done on the device from your coordinates. Space weather changes within hours. The app sees neither clouds nor moonlight, and a cloudy sky hides the aurora completely, however good the forecast is.
No accounts, no ads, no in-app purchases, no tracking. Your location stays on the phone and is not sent anywhere.
Data source: NOAA Space Weather Prediction Center (services.swpc.noaa.gov)
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
• Cloud cover and moon phase: clouds lower tonight's verdict, and overcast slots are dropped from the best hours
• Home Screen and Lock Screen widgets: chance, Kp and clouds at a glance
• Alerts now come from our server – even when the app is closed
The developer, Atsushi Koyama, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Location
- Identifiers
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Atsushi Koyama
- Size
- 1.8 MB
- Category
- Weather
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
English and 7 more
- English, Finnish, French, German, Icelandic, Japanese, Norwegian Bokmål, Swedish
- Age Rating
4+
- 4+
- Copyright
- © 2026 Atsushi Koyama