Thunder Over Louisville, the annual kickoff event of the
Kentucky Derby Festival, is an
airshow and
fireworks display in
Louisville,
Kentucky. It is generally held each April, 2 weeks before the first Saturday in May, or Derby Day. In years where Easter Sunday falls on the usually scheduled weekend, Thunder is moved a week earlier. It is the largest annual fireworks display in
North America and began as part of an opening ceremonies event in 1989 with daytime fireworks. 1990 brought the first nighttime fireworks event. It officially began in its current location along the Ohio River in 1991 with fireworks, and an annual air show was added in 1992.