The following guidelines are directly from the NFHS Rule Book.
1. Make sure that you go over the lightning procedures with the coaches and game administrator prior to the game.
2. When thunder is heard or a cloud-to-ground lightning bolt is observed, the thunderstorm is close enough to strike your location - suspend play immediately and seek shelter - note the restart.
3. Thirty minute rule - Once play has been suspended, wait at least 30 minutes prior to resuming play.
4. Any subsequent thunder or lighting during a 30 waiting period, reset the clock and begin another 30 waiting period
5. Hold periodic reviews with game administrator to determine the duration of the wait and then check the field for safety prior to resuming play.
6. Make sure you know what the restart is.
Here is a letter from the commissioner to school Director of Student Activities/Assistant Principals about the Spring 2018 season.