Most aurora apps show you a Kp number and leave you to work out what it means. GLOW answers the actual question: can I see the aurora, tonight, from where I am?

Why Location Changes Everything

The auroral oval is centred on the geomagnetic pole, not the geographic one. That is why Edinburgh sees far more aurora than places on the same latitude in Russia, and why Reykjavik sits under the oval while Anchorage does not. GLOW converts your coordinates to geomagnetic latitude and compares them against how far south — or north — the oval currently reaches.

The result is a straight answer: Overhead, On the horizon, Just possible, or Not visible. Plus the Kp your location actually needs, so you know what you are waiting for.

What You Get Free

• Live planetary K index with a clear visibility verdict for your location
• Chance of aurora directly overhead, from NOAA's OVATION nowcast
• Three-day forecast, with a marker showing the level your location needs
• Aurora alerts that only fire when it is dark and actually visible from you
• Choose your spot from a list, search for it, or enter coordinates
• Works offline with the last reading, and has no ads

GLOW Pro — One Payment, No Subscription

• Unlimited saved locations — home, the dark-sky spot up the coast, wherever you are travelling
• Live solar wind: Bz, field strength and wind speed. Bz turning southward is what actually drives a display, often before the Kp index catches up
• The aurora map — the whole oval as NOAA sees it right now, with your location marked
• A home screen widget showing current Kp and your verdict
• Advanced alerts: quiet hours so nothing wakes you at 3am, alerts for every saved location, and an option to stay silent unless Bz is southward, which cuts most false alarms

Both Hemispheres

Aurora australis is handled properly, not as an afterthought. Southern users get southern presets and are told to look south.

Privacy

GLOW has no account, no analytics and no advertising. There is no server: alerts are worked out on your own device. Nothing about you, your locations or your settings is collected or transmitted. Location permission is entirely optional — the app works fully without it.

The Data

Everything comes from the NOAA Space Weather Prediction Center, the official US source for space weather. It is public domain and updated continuously.

A Note On Expectations

No forecast can promise an aurora. Space weather changes fast, cloud gets in the way, and a bright moon washes out a weak display. GLOW tells you honestly when conditions are worth going outside for — and, just as usefully, when they are not.