About the data

The source

The Storm Events Database is the federal record of storms reported to the National Weather Service, maintained by NOAA's National Centers for Environmental Information. It runs from 1950; hail events appear from 1955 onward, when hail joined the collection. The data is public domain, and NCEI publishes updates monthly.

HailHistory ingests every yearly details file, keeps the events typed as hail, and rolls them up by county FIPS code. Coverage is the 50 states plus D.C., county-filed events only: marine hail, the handful of events filed against forecast zones rather than counties, a small number of rows with unresolvable county codes, and events in Puerto Rico and the U.S. Virgin Islands are excluded — together well under 1% of the source rows. The result: 421,342 events across 3,097 of 3,143 counties as of the current copy, which includes events through April 2026. Event narratives quoted on county pages are the reports as filed (public records, lightly trimmed for length).

What a county page shows

Event counts by decade and month, the count of 1″-and-larger and 2″-and-larger events, the largest recorded stone with its date, the most recent events, and the core-sample timeline — one mark per recorded event since 1955, sized by measured diameter. Sizes map to household names (quarter, golf ball, baseball) using the National Weather Service equivalents on the actual-size chart.

What the record honestly can't tell you

Storm Events contains what was reported. Sparse counties under-report; small hail often goes unfiled; reporting improved dramatically after the mid-1990s with spotter networks and digital filing. So a thin record is weak evidence of a calm climate, and a missing date is not proof a storm didn't happen. Every county page repeats this, because it's the single most important caveat in the data.

And a recorded event is not a damage assessment. Hail varies block by block; whether a specific roof was hit is an inspection question. HailHistory never gives insurance advice, never estimates damage, and never says whether you have a claim — for that, talk to your insurer or a licensed roofer.

Freshness

NCEI updates the database monthly, typically a few weeks behind real time. This site's copy is rebuilt from the source files on that cadence; the "data through" date in the header of every page comes from the newest event actually present, never from an assumption.

Independence

HailHistory is an independent reference site. It is not affiliated with NOAA, the National Weather Service, or any insurer or roofing company — and it links to no one it has a stake in.