What did the thunder say after the lightning?

The humor in this weather-themed gag zings from a clever bit of wordplay combined with an understanding of how thunderstorms work. The punchline plays on two meanings of "behind": literally, how thunder follows lightning, and metaphorically, how it still makes a powerful impact. It's a classic example of setting up an expectation based on one meaning and then delivering a twist with another, creating a satisfying "aha!" moment.

Scientifically speaking, the joke is spot-on. We see lightning flash almost instantaneously because light travels incredibly fast. Sound, on the other hand, moves much slower. That's why there's always a noticeable delay between the brilliant visual of a lightning strike and the booming rumble of its accompanying thunder. The further away the storm, the longer that lag between seeing the flash (Review) and hearing the crash.

So, while thunder might arrive a moment later, its mighty roar certainly leaves a lasting "impression" on anyone experiencing a storm. This joke perfectly captures that common observation in a lighthearted, relatable way, making it a cracking bit of weather humor that relies on both scientific fact and linguistic fun.