Thunderstorm distance provides a simple way to estimate how far lightning is by timing the interval between a visible flash and the following thunder, and it displays the result in kilometers or miles to support quick situational awareness.

How it works

The app measures the time between the flash and the thunder; because sound travels at roughly 343 m/s, about 3 seconds corresponds to 1 kilometer and about 5 seconds corresponds to 1 mile. Results are approximate and can vary with local conditions and elevation.

Features

Thunderstorm distance offers a manual timer to record the flash-to-thunder interval, selectable output in kilometers or miles, and an optional microphone-based detection mode to assist timing (microphone permission is required). The app provides a clear numerical estimate intended for general guidance rather than precise measurement.

Usage and safety

To use Thunderstorm distance, start the timer when you see lightning and stop it when you hear thunder, then use the displayed distance as an approximation and seek shelter when storms are nearby; this tool does not replace official weather warnings or professional advice.