After a thunderstorm, how long should you wait before reporting it has ended?

When determining how long to wait before reporting that a thunderstorm has ended, the recommended time is 15 minutes. This duration is significant because it allows the observer to ensure that the storm's main characteristics have indeed passed. After a thunderstorm has subsided, waiting 15 minutes helps confirm that there are no ongoing hazardous weather conditions, such as additional lightning or associated severe weather events.

This practice is rooted in an effort to provide accurate and reliable weather observations, which are critical for safety and for the proper functioning of meteorological reporting systems. The decision to wait this specific amount of time balances the need for prompt reporting while ensuring that the weather conditions have truly stabilized and are no longer hazardous. Thus, 15 minutes is the standard timeframe used to ascertain the end of a thunderstorm effectively.