Before It Strikes
Before It Strikes
There is no distance at which lightning nearby is fully safe, but 8 miles is the line official safety plans use: when lightning is within 8 miles, get inside. Lightning regularly reaches 10 miles from the storm, and a bolt from the blue has been documented 20 miles out under clear sky. If you can hear thunder at all, you are close enough to be hit.
NOAA sets three trigger distances for outdoor venues: 15 miles to start monitoring, 12 miles to prepare, and 8 miles to shelter. Eight was chosen as the minimum because most strikes fall within 8 miles of a storm, but about one in five land beyond it. It is the floor of the safety plan, not a comfortable buffer.
Counting seconds between the flash and the thunder and dividing by five gives rough miles, but it only works when you can hear thunder, and thunder rarely carries more than 10 miles. Real-time lightning detection is the reliable way. Before It Strikes shows the distance and direction of the nearest strike to any place you save, and warns you as a storm crosses each ring.
Lightning is visible more than 100 miles away, so a silent flash on the horizon is far off. It is not harmless. Watch which way the storm is moving, because a storm at 30 miles can be at 8 miles within the hour.
Official safety plans shelter when lightning is within 8 miles. Lightning regularly strikes 10 miles from a storm and has struck 20 miles away. If you can hear thunder you are within range.
Count the seconds from flash to thunder and divide by five for miles. Real-time lightning detection is more reliable, since thunder rarely carries beyond 10 miles.
Guidance on this page follows the National Weather Service lightning safety toolkit and the Lightning Safety Guide for Sports and Special Events published by CISA and the National Center for Spectator Sports Safety and Security (May 2026). Official NWS warnings always take precedence.
← Back to Before It Strikes