Clear North: Aurora Alerts

Most aurora alerts tell you the sun is busy. Clear North tells you whether you can actually see the lights tonight.

An alert only fires when all three are true at your location:
• Activity is high enough for your latitude
• It is dark (the sun is well below the horizon)
• The sky is clear enough (low cloud cover)

If one fails, Clear North says which one: "Not enough activity: Kp 5, you need 6", or "Too cloudy: 94% cover".

TONIGHT (free)
A clear verdict (Likely, Possible or Unlikely), the best window to look, how high above the horizon to look, and an hour-by-hour table of activity, cloud and darkness.

ALERTS (Clear North Pro)
A push notification only when tonight is Likely. You choose a nightly limit, quiet hours, an optional heads-up before dusk, and whether to break through for major storms. Time Sensitive delivery so a real show is not buried.

OUTLOOK (Clear North Pro)
The next three nights, a 27-day activity outlook, when an active region returns, and plain-English space-weather events.

Also: a red night-vision mode that keeps your eyes dark-adapted in the field. Works with Dynamic Type and VoiceOver.

PRIVATE BY DESIGN
No account. No tracking. Your location is rounded on your phone to a 0.5° grid cell (about 35 miles) before anything is sent; precise coordinates never leave the device. To show a place name, only the rounded cell centre is sent to Apple's geocoder.

Clear North Pro: 7-day free trial, then a yearly plan, or a one-time lifetime unlock. Manage or cancel in the app (Alerts > Manage subscription) or in Settings. Prices shown in the app come from the App Store.

Data: NOAA Space Weather Prediction Center and MET Norway (Norwegian Meteorological Institute).

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://mattdonders.com/apps/clear-north/privacy/