Rule 702
Definition
- Related pages
- 4
- Last revised
- 23 August 2026
Rule 702 of the Federal Rules of Evidence governs expert testimony in federal court, and most states have adopted it or something close to it. A witness qualified by knowledge, skill, experience, training or education may give an opinion if the proponent shows it is more likely than not that the testimony will help the trier of fact, is based on sufficient facts or data, is the product of reliable principles and methods, and reflects a reliable application of those methods to the facts of the case. The judge decides those questions before the jury hears the witness.
The rule is the codification of the Supreme Court's gatekeeping cases, Daubert and Kumho Tire, and its most recent amendment sharpened two points: that the proponent carries the burden on each element by a preponderance, and that a court must police not only whether the method is reliable but whether the expert's conclusion goes further than the method supports. An expert who states a conclusion with more certainty than the data allows is outside the rule.
For weather evidence the rule asks a plain question of every exhibit: what facts or data the opinion rests on, and whether they can be checked. A record that names its sources, states its method, keeps what was measured apart from what was detected and can be verified against the archive is the kind of data the rule contemplates. A summary that cannot say where its figures came from is not.
In the report
How the document prints it
The report is structured around the questions the rule asks of its data. The Sources and method section names each source, states how it was searched and what it can establish, and cites its URL; the Records show every row the findings rest on; the measured and estimated marks and the word estimated say which figures are data and which are analysis; and the Limitations state what the archive could not cover. The document offers no opinion, so it is not itself expert testimony; it is the facts or data an expert's testimony can rest on, with a fingerprint and a verification address so the copy in evidence can be checked against the one issued.
From the record
The facts or data, as the archive holds them
- Record from
- 1996
- Independent sources
- 9
- Searched for every address
- 4
- Kinds of evidence
- 4
The facts or data behind a report reach back to 1996 and come from 9 independent sources, 4 of them national, across 4 kinds of evidence. Every one is named in the document's Sources and method, which is where the rule's question is answered.
Measured Detected, not measured
The page these figures come fromRelated
The terms this page uses and the guides that go further. Each is shown against its own example from the record.
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Term
Forensic meteorologist
A meteorologist who reconstructs past weather at a place and time for a legal or insurance matter and testifies to it.
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Guide
Automated weather reports in court: what survives a challenge
Two Florida courts excluded wind figures taken from commercial weather products because nobody could verify how they were made. This guide states what those rulings turned on, what Rule 702 asks of a figure and of the person citing it, what independent corroboration means as a count, and what a report has to say about itself to be cited.
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Term
Independent source
A record-keeping route by which a storm reached the archive, counted once however many rows it produced, so that agreement between routes can be measured.
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Term
MESH
A radar algorithm's estimate of the largest hail a storm could have produced over a point: an analysis, detected and not measured, never a measurement.
Sources
The primary references. Each opens on the agency's own site.
The glossary defines the word. The report is what uses it.
Everything above is definition: what the word means in the document, and what it does not. None of it says what reached one roof.
Run the address and the archive is searched at the property: the storm, the date, the measured size, the distance and bearing from the roof, and the federal record each figure came from, in a document that states its own method. About a minute.
How this page is made
- The text
- Written by the editors and last revised 23 August 2026. It explains the record and how the report reads it; it contains no figure of its own.
- The example
- Drawn from the archive when the page was compiled, 24 August 2026, and rebuilt daily as the record deepens. Every figure in the panel marked From the record is computed, not written, and links to the page it came from.
- Measured and detected
- A report from a person or an instrument is measured. A radar-derived size is detected, not measured, and is marked as such, here and in every document we issue. The two are never added together.
- What this is not
- A definition of a word the report uses. It is not a report on any property, and it states no opinion about one. The coverage page states what the record holds, by kind and by year.
About this record
Everything here is reproduced from public federal and volunteer weather records, as the agencies and observer networks that publish them released it. Titan Weather compiles the record; it does not observe the weather, and it is not affiliated with any source it cites.
No archive holds everything. Storms cross places where nobody is standing, instruments and spotters cover some areas better than others, sources revise their records, and recent reports can take weeks to arrive and settle. Where this page shows nothing, nothing was found in the sources searched, within the period and area it states. That is not a finding that no weather occurred.
These pages describe the public record near a place or on a date. They do not establish what reached any particular property, and nothing here is insurance, legal or engineering advice.