Grayson County, Texas

What hazards hit Grayson County most?

The most frequent records are hail reports: 486 since 1955. 55% of its hail reports since 1955 fell in April and May. The rank column places the county among Texas's counties by days with a record per 1,000 square miles of land over each hazard's complete period.

Source: NOAA NCEI Storm Events Database (county and forecast-zone records attributed to the county; a zone record shows its own totals on each county it covers). Days: dates with at least one record of the hazard in the county. Ranks: days with a record per 1,000 square miles of land (Census Bureau 2024 Gazetteer), since 1950 for tornadoes, 1955 for hail and thunderstorm wind, 1996 for the rest.

How many tornadoes has Grayson County had?

NOAA records 72 tornadoes in Grayson County from 1952 to 2025, the strongest rated F3, with 3 deaths and 65 injuries recorded in the county. That is 42nd of 254 Texas counties by days with tornadoes per 1,000 square miles since 1950. A tornado that crossed a county line is counted in each county it touched, with the length of its path inside the county.

Counted as whole tornadoes rather than county records, the Storm Prediction Center's database holds 72 tornadoes whose track touched Grayson County since 1950 (NOAA's county records number 72, the same count); along their whole tracks they killed 5 people, 3 of them in Grayson County.

Map of the strongest tornado tracks in Texas.

Source: NOAA NCEI Storm Events Database, tornado records by county (path length in the county, maximum width); ratings as published: F scale before February 1, 2007, EF scale after. Whole-track figures: NOAA Storm Prediction Center tornado database (1950-2025). SPC severe weather database.

When was the last damaging storm in Grayson County?

The most recent record with damage, injuries or deaths is the May 10, 2026 hail ($10,000 in damage in 2025 dollars).

A trained spotter reported 2 inch diameter hail between Southmayd and Sherman.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 1333292)

Source: NOAA NCEI Storm Events Database; every record of 2025-2026 is listed, earlier ones when they caused deaths, injuries or $250,000 of damage (2025 dollars), and every tornado.

The deadliest and costliest records

A damage figure marked "step" is a record from before 1993: NOAA then filed damage by category, and the figure is the category as entered, in the dollars of that year, not an estimate of the loss.

Source: NOAA NCEI Storm Events Database: deaths and injuries direct and indirect; damage is property plus crops as estimated by the National Weather Service, converted to 2025 dollars.

Is it getting more frequent?

Records per decade for Grayson County's most frequent hazards. Counts rose everywhere after 1996, when NOAA began recording every event type, so compare decades within a hazard's complete period only (the shaded cells come before it).

Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).

What time of year?

55% of its hail reports since 1955 fell in April and May. The two busiest months are in violet.

Source: NOAA NCEI Storm Events Database, records by the month they began.

Federal disaster declarations for Grayson County

FEMA's register lists 21 declarations that include Grayson County: 12 major disasters, 9 emergencies and 0 fire management assistance declarations. Most were for severe storm (5) and fire (4).

Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), declarations through October 2, 2026; one declaration is counted once however many areas it names. OpenFEMA dataset page.

How many floods has Grayson County had?

NOAA's Storm Events Database holds 118 flood or flash flood records for Grayson County from 1996 to 2026, on 73 days, with 5 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Grayson County ranks 402nd of 2,942 U.S. counties.

The National Flood Insurance Program has paid $18.3 million on 743 claims filed in Grayson County; the most in one year was 152 in 1986. Claims count insured losses only: uninsured flood damage is not in this file.

Source: FEMA OpenFEMA NFIP Redacted Claims, as of September 8, 2026; claims by year of loss, payments in the dollars of the year paid. OpenFEMA dataset page.

FEMA's modeled risk for Grayson County

FEMA's National Risk Index rates Grayson County Relatively Low overall, with an expected annual loss of $42.6 million. These are FEMA's model estimates of future loss from 18 hazards, not a count of what happened; they can differ from the record above.

Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.

Counties that share a border with Grayson County

1. Denton County 1,844
2. Collin County 1,590
3. Grayson County 1,300
4. Cooke County 922
5. Bryan County, OK 863
6. Fannin County 804
7. Love County, OK 698
8. Marshall County, OK 636

Source: U.S. Census Bureau county adjacency file; NOAA NCEI Storm Events Database, records since 1950. The Census Bureau's adjacency file.

Next

• Tornadoes in TexasEvery Texas tornado since 1950 and the counties with the most per square mile
• Hail in TexasThe state's hail reports, by county, year and month
• The Texas recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in Grayson CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Grayson County's FEMA declarations (CSV)21 rows: every declaration that named the county, for your own analysis