Name: Aurora Forecast – Northern Lights for Eye & Camera
Rating: 5 (1 reviews)
Author: RunnerUp

A live northern lights nowcast and forecast for your exact location. The app gives a 0–100 score for probability to see the northern lights with the naked eye or (phone) camera based on live space weather data.

The score is based on live space weather data, as well as data at your current location: 

• Live Kp: the half-hourly Hp30 index from GFZ Potsdam, updated with live solar wind (Bz, speed) information, corrected for when it reaches Earth.
• Hemispheric Power: the energy input of the Aurora
• Ring current (Dst index): in big storms this parameter accounts for the aurora oval being visible further south.
• Your magnetic latitude and where the auroral oval sits at this time of night. 
• Time of day, moonlight and cloud cover.
• Four settings for light pollution.

Separate scores are calculated for visual observation of the Aurora, as well as capturing the Aurora by camera, as its easier to observe the Aurora by camera.

Features in the app: 

• Glance: A bar going from 0-100, matching the calculated score.
• Main-screen: separate scores for eye and camera. Additional info what is limiting in the current score (e.g. daylight). Also, the expected best time to observe the aurora in the next 18 hours is given.
• Tonight (introduced in 1.1): score for the coming eighteen hours, with predicted camera and eye scores.
• Why this score (introduced in 1.1): gives a breakdown on what the current score is based on, and what is most detrimental for the current score.
• Details: a compass on where to look to have the best chance to see the aurora. Also additional information on the current space weather is given. 
• Three days forecast: Thresholds are included when the Kp is high enough to see the aurora by eye or camera. 
• Alerts (hold UP) can be set when the score exceeds a threshold for camera and / or eye detection. Additional options for setting sleeping (quiet) hours, as well as receiving alerts ahead of time when space weather is peaking and expected to exceed the defined alarm thresholds.
• Night-red (hold UP): an additional setting to dim the screen to red during nighttime to protect eye sensitivity for optimal aurora observation.

Works in both hemispheres. Refreshes every 15 minutes after dark and hourly by day. Needs a phone connection (Garmin Connect app) for data, and a GPS position. The location is refreshed when you open the app.

Space weather is hard to predict: the score is an informed estimate, not a guarantee.

Support: use "Contact Developer" on this store page. Questions and bug reports are welcome. 

Data: NOAA Space Weather Prediction Center. Hp30 index: GFZ Potsdam (CC BY 4.0). Dst index: WDC for Geomagnetism, Kyoto. Weather data by Open-Meteo.com (CC BY 4.0).

Privacy
Aurora Forecast has no account, no ads and no analytics, and the developer collects no personal data.

• Your exact location stays on your watch. To get cloud cover, the watch asks Open-Meteo for the forecast at your location rounded to 0.1 degree (about 10 km), through your phone’s connection. Open-Meteo receives that rounded location and your phone’s IP address, as with any web request.
• Space weather comes from NOAA; those requests contain no location.
• Settings and the last data are stored on the watch only.