Bulletin #2315, Maine Farm Safety Program: Lightning Safety (PDF) By Dawna L. Cyr, Farm Safety Project Assistant, and Steven B. Johnson, Ph.D., Extension Crops Specialist For information about UMaine Extension programs and resources, visit extension.umaine.edu.Find more of our publications and books at extension.umaine.edu/publications/. Thunderstorms and lightning are most likely to develop on hot, humid days.