When thunder roars, head indoors: Did you know 20 percent of lightning fatalities occur when people are close to home?

Five people have been struck and killed by lightning so far this year in the United States, with all five of the deaths occurring in the South.

The number of deaths as of June 20 is one more than this time last year, a year that ended up setting an all-time record low for lightning deaths in recorded history.

Two of this year's victims were enjoying recreational activities when they were struck, while the other three had been working outdoors.

While lightning can claim lives all year round, the summer season is the most dangerous time of year for lightning in the U.S.

Based on a 10-year average compiled by the National Oceanic and Atmospheric Administration (NOAA), the months of June and July have the most lightning fatalities with an average of six and 10 deaths per month, respectively.

It's not uncommon to see more lightning-related deaths across the South, because in some areas, afternoon thunderstorms are often a daily occurrence, according to John Jensenius, lightning safety specialist for the National Weather Service (NWS).

"Typically, we do see more lightning deaths in southern areas," Jensenius said. "Southern areas generally have more lightning than northern areas, and thunderstorms are common during a much longer season."

Particularly vulnerable locations include Florida and portions of the Gulf coast, where the combination of the amount of lightning and the number of people partaking in outdoor activities puts many lives at risk, he added.

While there are several precautionary steps to avoid lightning, such as checking the forecast, the most important thing to remember is the saying "when thunder roars, go indoors."

During June 24-30, the National Lightning Safety Council will promote its Lightning Safety Awareness Week. Since this awareness initiative launched in 2001, the number of lighting fatalities per year in the U.S. have dropped from about 50 to 30.

Those who work outdoors for a living should remember to wait at least 30 minutes until the last clap of thunder is heard before returning to work.

If you can't make it into an indoor shelter, there are several safety tips if you're caught outside in a thunderstorms.

Take a look at some eerily beautiful lightning photos:

An important thing to keep in mind is that even if you're close to your home, that doesn't mean you're any less likely to avoid being struck. The sound of thunder should serve as an immediate reminder to head inside.

One of this year's victims, a 7-year-old boy, was struck and killed when he was playing under a tree outside his home in McKenzie, Tennessee.

"Overall, about 20 percent of lightning fatalities are related to activities around the home," Jensenius said. "Lightning happens instantaneously, but unfortunately people often wait until they hear a until they hear a loud clap of thunder from a nearby lightning strike before going inside."

Jensenius said that lightning fatality statistics show that people do take more chances when they're closer to home, whether it's doing yard work, walking to or from a car or simply waiting too long to head inside.

"Unfortunately, taking chances sometimes results in a lightning death or injury," he said.