SUNDAY, July 19, 2009 (HealthDay News) -- While making the most of long summer days, keep in mind that lightning activity peaks during the hot-weather months -- and don't assume you're safe just because you're indoors.
On average, about 50 people are killed by lightning in the United States each year, according to the National Weather Service. Lightning strikes caused 28 deaths in 2008 and there have been 23 lightning-related deaths so far this year.
"Follow the rule: 'When thunder roars, go indoors,'" Dr. Mary Ann Cooper, director of the lightning injury research program at the University of Illinois at Chicago, said in a news release.
Once inside, don't use landline phones, wired computers or video games.
"We are seeing an increasing proportion of people injured indoors using PlayStations and other hard-wired video games, even though they knew to unplug their computers to prevent lightning damage," Cooper said.
Wireless devices such as cell phones and iPods don't attract lightning.
If it's not possible to go indoors, seek shelter in a hardtop car, bus or truck. Never go under a tree during a lightning storm, Cooper advised.
Don't go back outside immediately after a storm appears to be over, she added. "Wait 30 minutes after the last crack of thunder or flash of lightning before resuming [outdoor] activities or driving home," Cooper said.
The U.S. National Weather Service has more about lightning safety.