Blah. Forensic meteorologists.

But for forensic meteorologists, who use the science of weather to testify in court about what has already happened, rather than predict what will occur, business could soon see an uptick.

In cases around the nation, meteorologists have played pivotal roles in determining guilt or innocence, or in establishing monetary damages. In fact, their testimony can be as persuasive as the types of scientific evidence — DNA and fingerprints, for instance — that are considered unimpeachable facts.

“Wherever the data takes us, we just tell the truth,” saidStephen Wistar, a senior forensic meteorologist forAccuWeather, whose experts have provided testimony in hundreds of courtrooms.

Mr. Wistar has testified mostly in civil cases, though he has also been called on in criminal cases, he said. He is asked to testify about things like the frequency of certain weather occurrences, or to provide precise details about conditions including temperatures and wind speeds.

Expert witnesses offer opinion, not the truth.