On hazy days, you don't know a storm is coming until it's upon you. If you're going to the beach, check the forecast and be prepared to move quickly if thunderstorms are expected. A simple AM radio can warn beachgoers of impending storms and lightning problems. Stay out of the water. If no building or other standing shelter is nearby, get in an automobile.
Automobiles generally are safe and offer excellent lightning protection.
If no shelter is available, seek the lowest spot you can find. Don't be the highest object on the horizon, and avoid open spaces. Don't sit under beach umbrellas. Stay away from metal objects. They will easily assume an induced charge and become a good candidate for a lightning strike.