Frequently Asked Questions (FAQ)

The inventors of the aurora forecast app based on machine learning predictions of ground magnetic perturbations are Prof. Gabor Toth, Hongfan Chen and Aniket Jivani. An initial prototype app was developed by Dr. Xiantong Wang. The GeoDGP model was developed by Hongfan Chen in collaboration with Professors Gabor Toth, Xun Huan, and Yang Chen. The data pipeline obtaining real-time observations was implemented by Aniket Jivani and Hongfan Chen. The frontend app was developed by Gabor Toth and David Benkes-Toth. App icon and title design were created by David Benkes-Toth. The backend database and server was developed by Jozsef Hollosi, who also came up with the AuroraTonight name. Professors Tuija Pulkkinen and Shasha Zou provided valuable ideas.

is a progressive web app (PWA) that works on mobile devices and desktop computers alike. You get full functionality by opening our web page with a browser on any device with internet access. A PWA can also be installed on your mobile device and used just like a regular app, but it does not require going through an app store.

On an Android phone, you can install the app by simply clicking on the blue "Install" button that shows up at the top right of the screen when you first access the web page. After installation completes, which is shown at the top, AuroraTonight will be among the other apps shown by the icon. You can then add the app to your home screen. The app will ask for permission to send you notifications, which is needed to receive Aurora Watch and Aurora Alert app notifications. You can change this permission by holding down on the app icon and clicking on "Site Settings" and then "Notifications".

On an Apple device, open the AuroraTonight web page in Safari, click on the three vertical dots at the bottom, then click on "Share", scroll down and click on "Add to Home Screen". Once installed, AuroraTonight will be among your other apps shown with the icon. Open the app and allow notifications when prompted to receive Aurora Watch and Aurora Alert app notifications. You can change this permission by going to Settings > Notifications.

On the main page, the top panel contains the logo that opens the University of Michigan Aurora page. The blue diagonal arrow indicates that the link is external, so after opening it, press the back button to return to the app. On the settings and info pages, the logo is replaced with the icon that returns you to the main page. Clicking on the app name also returns to the top of the main page. The share button lets you recommend the app to others.

The bottom panel contains the icon that opens the settings and the icon that opens the information page. On the main page you will see next to that the last time the forecast was updated. Clicking on this box or the icon refreshes the forecast data. The forecast is updated every 3 minutes on the server. You can also refresh the page by pulling down on mobile devices. On the other pages, the last update time and the refresh icon are replaced with the icon that returns you to the main page.

The main page shows the chance of seeing the aurora at or near the selected location in the next 90 to 120 minutes. If you are subscribed to local Aurora Alerts, clicking on this box provides a detailed Local Alert Report. Below this box are the hours of darkness, the Clear Sky forecast, the global magnetic activity forecast (D scale) and the multi-day aurora watch prediction (G scale). Under this your subscription status for local Aurora Alerts and global Aurora Watch notifications are shown. Scroll down to see our regional aurora forecast map, the clear sky forecast by NOAA, the polar magnetic activity movie from our model, the NOAA aurora prediction map, NASA solar wind observations and the observed and predicted Dst indexes. Use the time slider below the regional map to see how the aurora and clear sky forecasts evolve. The selected location is indicated by the symbol. The plot at the bottom is interactive, so you can touch the lines to see the values.

You can change the location by clicking on the location box at the top of the page or in the General Settings. If you choose the GPS based location, there will be a behind the location name, or if you decide to use IP-based location, the icon will be shown. When selecting a fixed location, there will be a list of matches. Click on one to select it. To check the surrounding area, set the distance range. The distance units can be set in the General Settings. Clicking on the Darkness Map box opens a map showing how dark the sky is around your location based on NASA night light observations. Clicking on the Clear Sky box opens an interactive chart with the Clear Sky Forecast for the night, while clicking on the Aurora Watch box opens the 3-day aurora watch forecast chart. To close a chart, click outside of it. Click on the Global Activity box to jump to the interactive solar wind and Dst index plot at the bottom of the main page. Clicking on other blue texts will take you to the relevant FAQ section or subscription panel.

The top of the settings page has the General Settings to set your location, distance range for local forecast, the distance unit (miles or kilometers) and time format (12-hour with AM/PM or 24-hour). Below that are the Aurora Alert and the Aurora Watch settings and subscription panels. All settings are saved automatically into your browser's local storage. Subscription settings are also saved on our server. See the data security FAQ for details.

Besides a high probability local aurora forecast, you need *dark* and *clear* sky! The top of the forecast page shows the probability of seeing the aurora near your location, the hours of darkness based on nautical twighlight (when the sun is 6 degrees below the horizon) and indicates how clear the sky is. Check out the regional aurora map to see the aurora forecast around your location indicated by the red marker. Click on the Darkness Map box to see the how dark the surrounding area is based on NASA observations. You can use this information to find a dark spot nearby. Click on the Clear Sky box to see the detailed Clear Sky Forecast by Open-Meteo, or look at the regional clear sky map based on the NOAA Global Forecast System (GFS) model. When you head out to see the aurora, make sure that the horizon is not blocked by trees or buildings. Get away from bright city lights, but remember that the aurora is large, so a few small light sources, including the moon, are no problem.

One of the easiest ways to see the aurora is using your phone's camera! Take a picture in night mode of the sky towards north (or south in the Southern hemisphere) and look at the recorded image. Our phones are much more sensitive to the colors of the aurora than our eyes, so you may take beautiful photos even when your eyes see only subtle hues. If you are lucky, you may see the aurora in other directions too, even directly above you!

Michigan researchers developed in 2024 a machine learning model trained on 28 years of observations of the solar wind, the Dst index and hundreds of ground-based magnetometers. Our GeoDGP model uses the observed time series of solar wind, magnetic field and Dst index to predict magnetic perturbations at any location on Earth with unprecedented accuracy. This is then used to forecast the aurora 1.5 to 2 hours ahead.

NOAA uses the Ovation 2020 empirical model based on historical satellite observations of the aurora. Ovation 2020 uses only the latest measurement of the solar wind and magnetic field without looking at the time history or the Dst/Kp indexes. As a result, it has limited validity for substorms and extreme geomagnetic storms. The SWPC aurora model provides a 0.5 to 1 hour forecast window.

The Aurora Alert is based on cutting-edge research at the University of Michigan resulting in a state-of-the-art machine learning model. This model can predict the global Dst index one hour ahead and local magnetic perturbations around the world 1.5 to 2 hours ahead based on the recent solar wind, magnetic field and Dst index observations. These magnetic disturbances are caused by charged particles that also cause the aurora. Subscribe to Local Aurora Alerts and catch the aurora!

This app provides notifications for the selected location. This can be a fixed location, or your current location based on GPS or IP address. You can set a distance range to receive alerts for locations near you. The aurora is only visible in darkness and can only be predicted reliably up to two hours ahead, so you may need to get an alert at night to catch it. Subscribe to local alert notifications to receive app notifications The alerts are only sent if all your preferred conditions are met, including a time period. If you subscribe to alerts for your current (GPS or IP) location, please remember to open the app if you travel to a distant destination, so that it can update your current location.

We provide the option of sending two or three notifications in a row to ensure you get alerted. If you want to wake up, select the "Triple" option and add the app as an exception to the do-not-disturb mode. To set things up, first give permission to push notifications. Next tap on the Test App Notification button on the settings page. Most likely you will not hear anything at this point, but this step is necessary to register the notification with your phone's operating system.

On an Android phone, go to your phone's Settings > Notifications > Advanced settings and swtich the "Manage notification categories..." option to ON. Here you can also set "Repeat notification alerts" option (for example every 3 minutes until dismissed) for our app if you want to. Next, go to Settings > Notifications > App notifications, find and tap on "Aurora" with the icon. Set "Allow notification" to ON if it is not on already. Tap on "Notification categories" at the bottom (this will only appear if you did all the previous steps), then set "General" to ON and tap on it. Next tap on "Sound", set the volume to a high level and select a "Custom" sound, for example "Treasure", that is long and loud enough to wake you up. Next go to Settings > Notifications > Do not disturb > App notifications and tap on the + sign (Add apps). Select the Aurora app and tap on "Done" to save the changes.

On an Apple device, go to Settings > Notifications and find the Aurora app with the icon. Tap on "Banner Style" and select "Persistent" to make sure the notification does not disappear until you act on it. Switch on the "Badges" and "Sound" and set "Show previews" to "Always". Go back to the main Settings page and tap on "Sounds & Haptics" and set the volume slider under the "Ringer and Alerts" section to a high level. You may want to select a notification sound, for example "Default Alerts > Classic > Update", that is long and loud enough to wake you up. This will set the sound for all notifications on your iPhone, so it may be best to do this before the nights when an Aurora Watch is in effect. Finally, go to Settings > Focus > Do Not Disturb > Apps > Allow Notification From. Tap on the + sign (Add App) and select Aurora with the icon. Tap on "Done" to save the changes.

Go back to the AuroraTonight app and tap on the Test App Notification button again. You should now hear the selected sound at a high volume even if your phone is in do-not-disturb mode. The notification sound will be off if you switch the phone to silent mode using the volume buttons (Android) or the side switch (iPhone). Note that the iPhone reduces the volume of the notification sound when the phone is in use. At night, when the phone is idle or locked, and the do-not-disturb mode is on but the volume is set high enough, you will hear multiple notifications in a row and they will be louder. Remember to plug in your Android phone to the charger at night, so that you can hear multiple notifications. If an Android phone is locked but not being charged, only the first notification will sound.

AuroraTonight can provide alerts for opportunities of seeing the aurora near you. It may be well worth driving an hour or two to see it. The alert checks for variations in probability of seeing the aurora and weather conditions. The selectable distance ranges (60 mi/100 km and 120 mi/200 km) correspond to 1 and 2 degrees latitude difference from your selected location.

The aurora forecast is uncertain just like weather forecast. Setting a 15% to 100% range means you will be alerted for even a small chance, while with an 80% to 100% range you will only be alerted for very highProbability events.

We check the local forecast for clear skies to make sure the aurora is visible from your location. Setting a range from 90% to 100% means you will be only alerted when the sky is mostly clear, while using a wider range allows for some clouds.

Aurora Report is available for users who subscribe to Aurora Alerts. It can be accessed by clicking on "Local Aurora Report" at the top of the main page. The report provides a detailed forecast of aurora probability and clear sky conditions in the selected distance range. The time slider below the regional map can be used to set the time for the report. When the time is closer to the current time, the maximum distance is reduced accounting for the travel time. If there are multiple locations within the distance range that meet the probability and clear sky criteria set in the settings page, a table will be shown with all these locations with the highest probability listed first.

Aurora Watch is based on the predicted space storm activity from solar observations. It takes from 1 to 3 days for a coronal mass ejection (CME) to arrive at Earth. The G scale is based on the maximum Kp index value in the forecast issued by NOAA Space Weather Prediction Center (SWPC). These long-term forecasts are very uncertain, this is why we call them Aurora Watch. You will get a free app notification if the forecast reaches the selected G scale value.

The G scale goes from 0 (quiet) to 5 (extreme) and it is obtained from the planetary K (Kp) index by subtracting 4, rounded to a non-negative integer. The Kp index measures the rate at which global magnetic perturbations evolve and goes up to 9.

The D scale goes from 0 (quiet) to 5 (extreme) and it is obtained from the magnitude of the storm time disturbance (Dst) index divided by 50. The Dst index measures the global magnetic field disturbance in nanotesla (nT) units. The more negative Dst, the stronger the geomagnetic storm. Peak Dst magnitudes can reach 500 nT in some very rare cases, but the scale is limited to D5.

The Aurora Borealis, or Northern Lights, is a natural light display in the sky, usually seen in high-latitude regions. It is caused by collisions between energetic particles from the solar wind and atoms in Earth's upper atmosphere. The Aurora Australis, or Southern Lights, occurs on the southern hemisphere.

The sun constantly releases a stream of charged particles called the solar wind. When the solar wind hits Earth's magnetic field, it is funneled towards the poles. These particles then excite oxygen (which glows green or red) and nitrogen (which glows blue or purple) atoms causing them to light up. The most important properties of the solar wind are its speed, density, and the magnetic field it carries. The solar wind changes dramatically during geomagnetic storms caused by space weather.

The typical speed of the solar wind is about 400 km/s (or 250 miles per second), and the typical density is about 5 particles per cubic centimeter. While this speed is already enormous by our standards, it can increase up to 2000 km/s during geomagnetic storms! The density can also increase to more than 50 particles per cubic centimeter. The speed and density combine to dynamic pressure that compresses Earth's magnetosphere, and this can create beautiful aurora. The solar wind speed also determines how long it takes to travel from the satellite at the L1 point to Earth. For example, at 400 km/s it takes about one hour, while at 800 km/s it takes only about 30 minutes. This is why the forecast time varies with the solar wind speed.

The typical magnitude of magnetic field vector (denoted by B and measured in nanotesla, nT) carried by the solar wind is about 5 nT. When it points southward (negative Bz), it reconnects with Earth's magnetic field that points northward, allowing solar wind energy to enter Earth's magnetosphere. This creates the best conditions for aurora. During geomagnetic storms Bz can reach -20 nT or even -50 nT for several hours causing huge events.

Geomagnetic storms are typically caused by increased solar wind speed and density, and a sustained strong southward magnetic field. The severity of a geomagnetic storm is often characterized by the storm-time disturbance (Dst) index. The aurora is brighter and visible at lower latitudes during geomagnetic storms.

Auroral activity is strongest during geomagnetic storms. The most intense storms happen when a coronal mass ejection (CME) from the sun sends a massive burst of energy toward Earth. These space storms have many impacts besides producing beautiful aurora: they can cause radio outage, GPS errors, satellite mafunctions or even power grid blackouts. This is why accurate space weather forecasts are so important.

Your privacy is very important to us. To provide local aurora and weather forecasts, we need to know your location. This can be your current location obtained from GPS (if you allow it) or IP address (which is less accurate and will not work with VPN) or you can provide the name of the city/town as the location. We round the latitude and longitude coordinates to 0.05 degrees (about 3 miles or 5 km) accuracy to protect your privacy.

If you do not subscribe to notifications, we do not store any information about you on our servers. All your settings are saved locally in your browser's local storage. If you clear your browser data or open the web page/app on another device or with a different browser, you will need to set them again.

If you subscribe to notifications, your user ID (a random string) and notification preferences will be saved on our server. We store this information securely and do not share it with anyone.

You can suspend or cancel your subscription to Aurora Alerts any time with a couple of clicks in the app. When you suspend your subscription, we delete your information from our server (and you will stop receiving notifications), but keep a summary on your phone so you can easily resume your subscription later if you wish. When you cancel your subscription to Aurora Alerts, we will delete all your information from our server and reset the notification settings to their default values on your phone. For the Aurora Watch notifications, you can simply switch it off and the corresponding information will be deleted from our server.

IP-based location determines your approximate location using your internet connection's IP address. This method does not require GPS permissions and works on any device with internet access. However, it is less accurate than GPS location, typically providing city-level accuracy rather than precise coordinates. IP location is automatically used as a fallback if GPS location fails, is denied, or times out. You can also manually choose IP location if you prefer not to share your precise GPS coordinates. When IP location is active, you'll see the icon next to your location name. IP-based location may not work with a VPN or proxy service, as these make the connection appear to originate from a different location than where you actually are.