They say lightning doesn't strike twice, but in 2018, it struck some states up to 2 million times. Recording and assessing lightning data is critical for public safety and for insurers to quantify risks and protect their insureds. According to the National Oceanic and Atmospheric Administration (NOAA), the U.S. averaged 51 annual lightning strike fatalities and several hundred injuries each year during the last 20 years, making it the second-leading weather event for U.S. fatalities. Examining where, when and how frequently lightning struck in 2018, environmental measurement specialist Vaisala recently published the findings of its Annual Lightning Report. Using data from Vaisala's National Lightning Detection Network and GLD360 global lightning detection network which monitor total lightning activity 24 hours a day, 365 days a year, Vaisala identified the top 10 states with the most cloud-to-ground lightning strikes in 2018.

Lightning strikes declined in 2018

Notably, this year's data shows there were nearly two million fewer lightning strikes in the U.S. in 2018 compared to the 10-year average — an 11% drop. Vaisala found 2018 had 17,804,321 negative cloud-to-ground flashes, the most common cloud-to-ground lightning, and the third-fewest flashes in the last 10 years. "The likely reason for the reduction is simply that there were fewer big storms," Ryan Said, Lightning Research Scientist at Vaisala explained in a statement. "Specifically, there were fewer days with very strong air mass contrasts across the Central Plains and Upper Midwest during the spring and summer of 2018, which contributes to the severe weather season." Related: 10 dangerous misconceptions about lightning safety

Other lightning data to consider

Looking at deeper data from Vaisala, the 2018 lightning report also identified which states had the highest lightning flash density per square mile, along with the top 10 dates that recorded the most lightning strikes. Overall, the top 10 worst dates for lightning strikes all occurred in the summer months between June and August. Detailed in the slideshow above are the top 10 states with the most cloud-to-ground lightning strikes in 2018. Related: After a disaster: Falling trees, rodent infestations and more