Hail size
Definition
- Related pages
- 5
- Last revised
- 23 August 2026
Hail size is the diameter of the largest stone observed at a place, given in inches or by the object on the Weather Service spotter chart it was compared with: a pea, a penny, a quarter, a golf ball, a baseball, each name standing for a fixed diameter. The chart exists because a spotter in a storm has a coin in a pocket more often than a ruler. The Weather Service sets a criterion at which hail counts as severe; warnings are issued against it and the record is logged against it.
The figure reaches the record by several routes that do not measure the same thing. A spotter's size is the largest stone found, not the typical one, picked up after some melting and compared by eye. An observer's size comes from a gauge or a hail pad at a fixed site. A radar-derived size is an estimate of the largest stone the storm could have produced over a grid cell, computed whether or not anything fell. A warning's tagged size is what a forecaster expected. A size is therefore never a bare number; it is a number and a method, and the method decides what the number can be cited for.
The product draws the size bands on the map from the same chart, keeps a measured size and a radar-derived size in separate columns with different marks, and never averages or adjusts one toward the other. Sub-severe sizes are kept and drawn, because they are what a claim most often asks about.
In the report
How the document prints it
In the report every hail record prints its size in inches to two decimals in the measurement column of the record table, with the mark that says whether it was measured or estimated, and the findings take the largest size from measured records only. The storm map shades the swath by size band, and the reading guide at the back reproduces the chart: each band's diameter range, the object it is named for, and whether it meets the severe criterion. A size read over the address from the radar analysis is printed as analyzed, in its own column, and never beside a ground measurement as though it were one.
From the record
23 Aug 2026
The largest sizes on the most recent severe hail day
- Severe hail criterion
- 1.00″
- Largest measured on the ground
- 1.75″
- Largest detected, not measured
- None
- Hail reports on the day
- 40
On 23 August 2026, the most recent day hail reached the 1.00″ criterion anywhere on record, the largest measured on the ground was 1.75″, among 40 hail reports carried by 2 independent sources. Each figure is a size and a method, and the two are kept in separate columns.
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
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.
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Term
Spotter report
An eyewitness report of hail, wind or a tornado made by a person at the scene and passed to a forecast office, with the place and time attached.
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Term
Hail swath
The area a storm is estimated to have dropped hail of a given size over, drawn on a map from radar analysis or traced between ground reports.
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Term
Severe thunderstorm warning
An official National Weather Service warning that a storm meeting the severe criteria for hail or wind is occurring or imminent inside a drawn area.
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Guide
Measured and detected: radar hail sizes against spotter reports
The record keeps a stone measured on the ground apart from a size computed from radar, because a court will ask which is which. This guide names the kinds of evidence as the report names them, states what a radar-derived size can and cannot say, explains why a measurement is drawn as a filled mark and a detection as a hollow one, and shows how to read the two on the same day.
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.