How far away was that lightning strike?
Flash-to-bang, done right. Tap when you see the flash and tap when you hear the thunder — or point the camera at the storm and let it measure hands-free. Temperature-adjusted speed of sound, storm trend, and a live radar & lightning map included.
⚡ Download free on Google PlaySee the flash, then tap. Hear the thunder, tap again. It times the flash-to-bang gap and works out how far away the strike hit — right here in your browser, no install.
Counting by hand works for one bolt. Strike Analyzer detects the flash and the thunder for you, corrects for temperature automatically, logs every strike, and tells you whether the storm is approaching or moving away — and roughly when it'll be overhead. Get it free on Google Play →
One big glove-friendly button. Tap at the flash, tap at the thunder, get the distance. Works anywhere, day or night, no permissions needed.
The camera watches for the flash while the microphone listens for the thunder onset, then pairs them automatically. Best after dark — set the phone down and watch the storm.
Auto mode saves the exact camera frame that triggered detection — your lightning photo, plus a copy tagged with distance, time, and GPS location.
Consecutive strikes reveal whether the storm is approaching or moving away, how fast, and roughly when it will be overhead.
Every measurement is kept — distance, time, flash-to-bang, GPS pin — and exports as CSV whenever you want it.
Weather radar with real-time lightning strikes, centered on you. Zoom in on your neighborhood or pan out to see the whole system moving through.
All flash and thunder detection runs entirely on your phone — your camera and mic data never leave the device. Location is optional, used only to GPS-tag photos, pull live temperature, and center the map on you.
Strike Analyzer is free with ads. A one-time Pro purchase — no subscription — removes ads and unlocks your full strike history (everything you logged while free unlocks retroactively).
| Free | Pro (one-time) | |
|---|---|---|
| Manual & auto measurement | Full | Full |
| Bolt photos & storm trend | Full | Full |
| Live radar & lightning map | Full | Full |
| Strike log | Last 5 strikes | Complete history |
| Ads | Small banner | None |
Strike Analyzer is not a safety device. Flash-to-bang distances are estimates and can be wrong. Never use this app to decide whether it is safe to stay outdoors.
If you can hear thunder, you are close enough to be struck. Follow the National Weather Service guidance: When Thunder Roars, Go Indoors — and stay there until 30 minutes after the last thunder.
Count the seconds between the flash and the thunder — roughly every 5 seconds is a mile (3 seconds per kilometer). Strike Analyzer does the math for you and adjusts for how temperature changes the speed of sound, so it's more accurate than counting in your head.
Light reaches you almost instantly; thunder travels about 343 m/s. The delay between seeing the flash and hearing the bang tells you the distance. Tap at each, or let the camera and mic detect them automatically.
No — Strike Analyzer is not a safety device and its distances are estimates. If you can hear thunder, you're close enough to be struck. When thunder roars, go indoors.
A National Weather Service guideline: if you count 30 seconds or fewer between the flash and the thunder, the lightning is within about six miles — go indoors. Then wait 30 minutes after the last thunder before heading back out. Use the 30-30 rule itself for safety calls, not any app's number.
Thirty minutes after the last clap of thunder, per the National Weather Service. Storms can still throw strikes several miles beyond the rain, so don't head back out on the first quiet gap.
Take a few measurements over a few minutes: if the flash-to-bang gap is shrinking, the storm is coming toward you; if it's growing, it's moving off. Strike Analyzer reads this automatically — its Storm Trend shows approaching, receding, or steady from your logged strikes, with the storm's speed and a rough time until it's overhead.
Yes, free with a small banner ad. A one-time Pro purchase (no subscription) removes ads and unlocks your complete strike history.