FAQ

How accurate is the arrival time? For organised storms an hour out, usually within 10–15 minutes, improving as they approach. Pop-up showers are harder and the app says when confidence is low. More on how it works.

Does it work outside the US? No — it relies on NOAA radar, which covers the continental US, Alaska, Hawaii, Puerto Rico and Guam.

Does it need internet? Yes, for radar and forecasts. If the signal drops it keeps showing the last data with its age, and the last briefing can still be played.

Where does the data come from? Radar: NOAA MRMS. Forecasts and alerts: the National Weather Service. Lightning: NOAA GOES satellites. Rivers: NOAA/NWS gauges. Wildfires: the national interagency fire data. Tides: NOAA CO-OPS. Snow: USDA SNOTEL. Maps: OpenStreetMap.

Is it a replacement for NOAA weather radio or phone emergency alerts? No. It relays the same NWS warnings and adds radar lead time, but it needs a network. Keep official channels on.

Do you sell my data or show ads? No and no.