In the 21st century the estimated attendance at Thunder has usually been approximately five times that of the main attraction, the Kentucky Derby.

Thunder Over Louisville began as a concept at a Kentucky Derby Festival workshop in the summer of 1988, after a decision had been made to have opening ceremonies for the first time.

Organized by multimedia producer Wayne Hettinger, owner of Visual Presentations, they featured a live stage show to introduce the festival theme song and the release of about 20,000 multicolored balloons—followed by daytime fireworks.

In 2006, McDonald's announced that they would be the title sponsor for Thunder Funder and donate 10 cents from the sale of every 32-ounce drink in a commemorative cup to the Derby Festival.

This is usually preceded by a short break in the fireworks and an audio score of "The Colonel Bogey March" as whistled in the movie Bridge on the River Kwai, often catching first time spectators, who believe the show has ended, by surprise.

Such counts do not include thousands of people who watch from area rooftops at "Thunder parties" held by individuals with proximity advantaged addresses in downtown, Old Louisville, Portland and the Butchertown neighborhood immediately upriver from downtown, as well as river adjacent neighborhoods in the Indiana communities of Clarksville and Jeffersonville.

In 2010, a computer glitch 30 seconds before the show during a pre-recorded minute long audio countdown to the fireworks caused an 18-minute delay while the problem was troubleshooted.

Due to the complexity of the event, including road closures, police presence, and technical requirements, there is no rain date for Thunder.

Officials would cancel if severe weather or lightning was imminent, and the fireworks could be delayed if heavy rain or wind was occurring at the time of the show.

[28] TV coverage of the fireworks received record ratings in 2006 due to cold temperatures which made many people choose to watch the show from home.

In 2005, The Kentucky Derby Festival started rotating the broadcast rights each year between 3 of the major Louisville network affiliates (WAVE-TV, WDRB, and WLKY).

After airing the coverage exclusively from 1991 to 2003, WHAS-TV chose not to participate in the rotation for several years after this agreement was made.