What this is, and where it breaks
Live lightning for Norway and Sweden. Data from The Norwegian Meteorological Institute, about seven seconds behind the strike.
The verdict
- Take cover
- A strike within 10 km in the last five minutes.
- Clearing
- The 30-minute clock is still running. Every new nearby strike restarts it.
- Inbound
- A tracked cell is on course to reach 10 km.
- All clear
- Neither, for 30 minutes.
Where it breaks
- Stopwatch
- The countdown measures time since the last nearby strike. It cannot anticipate a storm that has not started producing lightning.
- Hard cliff
- A strike at 10.1 km does not restart the clock. Real guidance is “if you can hear thunder” — nearer 16 km.
- Straight lines
- Cells split, stall and back-build. A fit below r² 0.35 shows no direction rather than guessing.
- One hour
- Anything older falls out of the window entirely.
- Lagging
- Lightning shows where a storm already discharged, never where one is forming. That is what the radar overlay is for.
Sources
MET Norway Frost (CC BY 4.0). Radar: RainViewer. Map: OpenFreeMap, OpenStreetMap. Search: Photon.
A hobby build on public data — not a safety-critical system. If you can hear thunder, you are close enough to be struck.
The Review tab replays the verdict over the archive and scores past calls against what actually arrived, so the accuracy claim is checkable rather than asserted.