What is the 30 minute lightning rule?

The 30-minute lightning rule is an important safety guideline for thunderstorm weather, consisting of two key indicators. First, if the interval between a lightning flash and thunder is less than 30 seconds, it indicates that the thunderstorm is within a 10-kilometre range. Second, after the last clap of thunder, one should wait 30 minutes before going outside to ensure the thunderstorm has moved completely away. This rule is based on the pattern of lightning activity: since thunderstorms move at a speed of approximately 40 kilometres per hour, a 30-minute interval can avoid residual risks. When taking shelter, windows and electronic devices should be turned off, contact with metal parts inside the vehicle should be avoided, and tall objects such as trees and utility poles should be avoided. This principle also applies to electric vehicles, whose metal bodies also provide lightning protection, but additional insulation protection for the high-voltage battery system should be considered.