FlashBang

Lightning distance estimator. Flash to bang.

Ever wondered how far away a lightning strike is? FlashBang tells you instantly - no counting, no mental arithmetic. It's a lightning distance calculator that lives in your browser toolbar, ready the moment the sky lights up. HOW IT WORKS ━━━━━━━━━━━━ Tap the button the moment you see lightning. Tap again when you hear the thunder. FlashBang calculates the distance using the speed of sound, adjusted for actual air temperature - more accurate than the basic "divide by 5" rule. FEATURES ━━━━━━━━ ⚡ One-button operation - tap to see, tap to hear 📍 Optional live weather - auto-fetches local temperature for accurate sound speed calculation (warmer air = faster sound = shorter distance) 📏 Results in both km and miles ↓↑ Trend indicators - see if the storm is approaching or moving away ⚠ Safety alert when a storm is within 5 km / 3 miles and closing 🕐 Session history with individual entry delete (corrects a mistimed tap) 🗑 Auto-clears after 48 hours THE SCIENCE ━━━━━━━━━━ This thunder distance calculator uses the formula v = 331.3 + (0.606 × T°C) rather than a fixed speed - because sound travels measurably faster in warm air than cold. At 8°C it moves at ~336 m/s; at 30°C it's ~349 m/s. Over a 10-second gap that's a real difference. Also known as the flash-to-bang method - the same technique used by meteorologists, outdoor safety professionals, and sports event managers to assess storm proximity. FlashBang puts it in your browser toolbar as a proper storm distance tool, ready when you need it. "Bolts from the blue" - strikes from apparently clear sky up to 10 miles from a storm - are rare but real. If you can hear thunder, you are within striking distance. When in doubt, seek shelter. No data collected. No account required. Works entirely in your browser.