Storm risk in Williamson County, Tennessee

FEMA's overall hazard score for Williamson County is 85.15 (Relatively Moderate), 468th of 3,144 counties. Hail scores 41.86 (Relatively Low), strong wind 89.12 (Relatively High) and tornado 88.87 (Relatively Moderate). Expected hail loss is $5.23 per $1 million of buildings a year; NOAA logged 105 hail reports in Williamson County from 2014 to June 2026.

FEMA National Risk Index, version December 2025, retrieved October 8, 2026. NOAA hail reports 2014 to June 2026.

Williamson County: expected yearly loss per $1 million of buildings for hail, strong wind and tornado, on a log scale, against all U.S. counties and the counties of TN$0.1$1$10$100$1,000Hail: $5.23 per $1 million, 2,402nd of 3,126 rated counties$5.23Hail2,402nd of 3,126 countiesStrong wind: $4.67 per $1 million, 2,640th of 3,121 rated counties$4.67Strong wind2,640th of 3,121 countiesTornado: $188 per $1 million, 1,630th of 3,144 rated counties$188Tornado1,630th of 3,144 counties
  • Williamson County, coloured by its FEMA rating
  • all U.S. counties
  • each county in the state
  • U.S. median
  • state median

Expected yearly loss per $1 million of buildings, log scale. Dot colour is FEMA’s rating band. The tornado lane counts everything exposed, not only buildings.

How FEMA rates Williamson County

HazardRatingScore (0 to 100)Rank in U.S.Rank in TN
OverallRelatively Moderate 85.15468 of 3,14411 of 95
HailRelatively Low 41.861,829 of 3,12630 of 95
Strong windRelatively High 89.12343 of 3,1267 of 95
TornadoRelatively Moderate 88.87351 of 3,12614 of 95

Expected yearly loss, in dollars

HazardThis county, total a yearPer $1M of buildingsState median countyU.S. median countyRank per $1M, U.S.Rank per $1M, state
Hail$321,339$5.23 $12$22 2,402 of 3,12668 of 95
Strong wind$286,610$4.67 $34$20 2,640 of 3,12192 of 95
Tornado$11,550,093$188 $403$199 1,630 of 3,14477 of 95

Rank 1 is the highest. Overall, hail and wind losses count buildings; the tornado row counts everything FEMA exposes, so it overstates building damage. Expected annual loss is an average over many years for the whole county, not a forecast for one roof.

What stands out in Williamson County

  • FEMA expects hail in Williamson County to cost $5.23 per $1 million of buildings a year: 0.23 times the U.S. median and 0.42 times the TN county median, ranked 2,402nd of 3,126 counties nationally and 68th of 95 in Tennessee.
  • FEMA expects strong wind in Williamson County to cost $4.67 per $1 million of buildings a year: 0.23 times the U.S. median and 0.14 times the TN county median, ranked 2,640th of 3,121 counties nationally and 92nd of 95 in Tennessee.
  • FEMA expects tornado in Williamson County to cost $188 per $1 million of buildings a year: 0.95 times the U.S. median and 0.47 times the TN county median, ranked 1,630th of 3,144 counties nationally and 77th of 95 in Tennessee.
  • Applying FEMA's estimate to a $673,700 home, the average yearly loss in Williamson County is about $3.53 for hail and $3.15 for wind before any deductible; at the U.S. median county rates it would be $15 and $14.
  • If the next years look like 2014 to 2025, a roof kept 20 years in Williamson County meets about 38.3 hail days of 1 inch or more; the median county in NOAA's file (1,275 counties) would give 35.0.
  • Built in 2001, the median home in Williamson County is 25 years old, so an original roof has outlived a 3-tab shingle (15 to 20 years) and is inside the rated life of an architectural one (25 to 30 years); 47.7% of its 94,418 homes are at least 26 years old.
  • March to June holds 87 of the 105 hail reports in Williamson County (83 percent); the quietest month is December, with 0 reports.

What hail and wind cost a home here in an average year

Enter a home value. The calculator applies Williamson County’s own loss rate: the county’s expected yearly loss divided by the value of its buildings. It starts at the Census median home value for the county.

$3.53hail, a year; $15 at the U.S. median county rate
$3.15strong wind, a year; $14 at the U.S. median county rate
$133hail and wind together over 20 years, at today’s rate

Formula: home value × Williamson County yearly loss ÷ building value. Hail: $321,339 ÷ $61,392,881,948 = 0.0000052. Wind: $286,610 ÷ $61,392,881,948 = 0.0000047. This is FEMA’s estimate of average damage to buildings and does not account for your deductible. Tornado is left out because FEMA’s tornado loss counts people and other exposure, not only buildings.

Read this as a yardstick. The rate is an average over every building in the county, from sheds to office towers, and over many years. Real losses come in rare, large storms; a roof with no damage in 19 years can need full replacement in the 20th. The figure is not a quote and not a prediction for one address.

Williamson County in plain numbers

  • Williamson County scores 85.15 in FEMA's overall hazard index (Relatively Moderate): 468th of 3,144 rated counties and 11th of 95 in Tennessee.
  • Hail scores 41.86 (Relatively Low). FEMA expects $321,339 of hail damage to buildings in Williamson County a year, which is $5.23 per $1 million of buildings, 0.23 times the U.S. median.
  • Strong wind scores 89.12 (Relatively High) with $286,610 of expected yearly building loss in Williamson County: $4.67 per $1 million of buildings, 0.23 times the U.S. median.
  • Tornado scores 88.87 (Relatively Moderate) and FEMA's expected yearly tornado loss is $11,550,093, counting everything exposed, or $188 per $1 million of buildings in Williamson County.
  • FEMA's own event record for Williamson County averages 3.50 hail events and 6.11 strong-wind events a year.
  • NOAA logged 105 hail reports in Williamson County between 2014 and June 2026, on 23 days with stones of 1 inch or more; the largest was 3 inches.
  • In Williamson County, FEMA counts buildings worth 61.39 billion dollars and 247,523 residents.
  • Social vulnerability is Very Low in Williamson County.
  • Community resilience there is Very High, for 247,523 residents.
  • 1 city in Williamson County is covered on this site: Franklin. 9 Census ZIP areas have more than half of their land in the county.
  • Our guide range for a 2,000 sq ft asphalt roof in Franklin is $6,090 to $13,485.
  • Williamson County ranks 158 of the 194 counties with a page here for hail loss per $1 million of buildings, 151 for wind and 114 for tornado.
  • In Williamson County, May is the busiest month with 49 of the 105 reports (47 percent), against 1 report in November.
  • Williamson County's worst year was 2025, with 6 hail days at 1 inch or more and 43 reports. At the 2014 to 2025 pace that is 1.92 such days a year, one about every 6.3 months.
  • The median home in Williamson County was built in 2001; 17.2% of its 94,418 housing units date from before 1980, 47.7% from before 2000 and 29.4% from 2010 on.
  • Census puts the median home value in Williamson County at $673,700, and 79.8% of homes are lived in by their owners.
  • 20,460 single-family building permits were issued in Williamson County from 2014 to 2025, about 216.7 per 1,000 homes, peaking in 2021.
  • NOAA lists 7 tornado tracks in Williamson County since 2014; the strongest was an EF1 on March 1, 2017 near Berrys Chapel, 10.48 miles long.
  • The fastest gust in NOAA's records for Williamson County is 85 mph on June 19, 2019 at Calle.
  • The nearest county with a page here is Rutherford County, 28 miles from the centre of Williamson County; its hail score is 59.45.
  • Across counties the median is one roofing firm for every 5,189 homes; Census counted 23 roofing contractor establishments in Williamson County in 2023, one for every 4,105 homes.

The hail record of Williamson County, year by year

NOAA logged 105 reports in Williamson County; hail of 1 inch or more fell on 23 days. That is 1.9 such days a year; the median county in NOAA’s file has 1.8.

Williamson County: NOAA hail reports per year, 2014 to June 2026, with the number of days that had hail of 1 inch or more010203040502014: 2 reports, 1 days at 1 inch or more, largest 1 inch142015: 4 reports, 2 days at 1 inch or more, largest 1.75 inch152016: 4 reports, 1 days at 1 inch or more, largest 1 inch162017: 1 reports, 1 days at 1 inch or more, largest 1 inch172018: 4 reports, 1 days at 1 inch or more, largest 1 inch182019: 4 reports, 2 days at 1 inch or more, largest 1.25 inch192020: 2 reports, 1 days at 1 inch or more, largest 1 inch202021: 13 reports, 2 days at 1 inch or more, largest 2.25 inch212022: 5 reports, 2 days at 1 inch or more, largest 1.75 inch222023: 5 reports, 2 days at 1 inch or more, largest 1.5 inch232024: 18 reports, 2 days at 1 inch or more, largest 3 inch242025: 43 reports, 6 days at 1 inch or more, largest 3 inch252026: 0 reports, 0 days at 1 inch or more, largest 0 inch26*
  • reports
  • days with hail of 1 inch or more
  • * 2026 runs to June only
Williamson County: NOAA hail reports by calendar month, 2014 to June 2026January: 2 reports2JanFebruary: 1 reports1FebMarch: 18 reports18MarApril: 9 reports9AprMay: 49 reports49MayJune: 11 reports11JunJuly: 9 reports9JulAugust: 2 reports2AugSeptember: 2 reports2SepOctober: 1 reports1OctNovember: 1 reports1NovDecember: 0 reports0Dec

Reports by calendar month, all years together. Peak: May, 49 reports.

The same numbers as a table (years with at least one report)
YearReportsDays, 1 inch or moreDays, 1.75 inch or moreLargest stoneDamage reported
20142101 in–
20154211.75 in–
20164101 in–
20171101 in–
20184101 in–
20194201.25 in–
20202101 in–
202113212.25 in–
20225211.75 in–
20235201.5 in–
202418223 in$100,000
202543643 in–

Biggest hail days in Williamson County

DateLargest stoneReports that dayDamage reportedNear
May 20, 20253 in25none recordedDouglas
May 26, 20243 in11$100,000Leipers Fork
April 3, 20252.5 in7none recordedCraigfield
March 27, 20212.25 in8none recordedCollege Grove
May 6, 20242 in6none recordedKirkland

Where large hail was reported

FEMA scores the county as a whole. NOAA’s reports show where inside Williamson County the big stones fell.

Reported hail locations, Williamson County

1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1 in hail1.25 in hail1.25 in hail1.25 in hail1.25 in hail1.25 in hail1.25 in hail1.25 in hail1.25 in hail1.25 in hail1.25 in hail1.25 in hail1.5 in hail1.5 in hail1.5 in hail1.5 in hail1.5 in hail1.5 in hail1.5 in hail1.5 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail1.75 in hail2 in hail2 in hail2 in hail2 in hail2 in hail2 in hail2 in hail2 in hail2 in hail2.25 in hail2.25 in hail2.5 in hail2.5 in hail2.75 in hail3 in hail3 in hail3 in hail Franklin
  • 561 to 1.74 in
  • 271.75 to 2.74 in, golf ball to tennis ball
  • 42.75 in and up, baseball

Largest plotted stone: 3 in. Bigger dots are bigger stones.

87 reports of 1 inch or larger have coordinates. Each dot is a reported location, not a storm path.

Sources: NOAA, Census county outline

Wind and tornado records for Williamson County

Fastest gusts in Williamson County

DateGustNear
June 19, 201985 mphCalle
March 1, 201781 mphLa Vergne
March 1, 201781 mphMallorys
November 5, 201875 mphThompsons Station

Strongest tornado tracks in Williamson County

DateScaleLengthInjured / killedNear
March 1, 2017EF110.48 mi0 / 0Berrys Chapel
March 30, 2025EF01.81 mi0 / 0Craigfield
August 12, 2023EF01.85 mi0 / 0Ewingville
May 9, 2021EF00.78 mi0 / 0Rudderville

7 tornado tracks in all since 2014; the strongest 4 are listed.

How old the roofs are

Census counts homes by the decade they were built. Under each bar is the number of hail days of 1 inch or more that an original roof from that decade has met, at Williamson County’s 2014 to 2025 pace of 1.92 such days a year. Most roofs have been replaced since; the row shows what a roof that never was would have taken.

Williamson County: share of homes by decade built, with the hail days at 1 inch or more that an original roof from each decade has met at the county's 2014 to 2025 ratepre-1940: 2.1% of homes2.1%<19401741940s: 0.6% of homes0.6%1940s1551950s: 1.6% of homes1.6%1950s1361960s: 3.6% of homes3.6%1960s1171970s: 9.4% of homes9.4%1970s981980s: 11.2% of homes11.2%1980s791990s: 19.2% of homes19.2%1990s592000s: 23.0% of homes23%2000s402010s: 26.5% of homes26.5%2010s212020+: 2.9% of homes2.9%2020+6

Bars: share of 94,418 housing units by decade built. Figures under the decade: hail days met by an original roof, at the county’s 2014 to 2025 pace. The pace of earlier years is unknown.

Median year built2001
Built before 198017.2%
Built before 200047.7%
Built since 201029.4%
Owner-occupied79.8%
Median home value$673,700
Single-family permits, 2014 to 202520,460
Permits per 1,000 homes216.7

Asphalt shingles are rated 15 to 20 years (3-tab) and 25 to 30 years (architectural). Source: Census ACS 2019 to 2023 and Building Permits Survey.

Roofers and past disasters in Williamson County

Roofing firms in Williamson County

Roofing contractor establishments, 202323
Change since 2016+16 (+229%)
Homes per roofing firm4,105
Median across counties5,189
Employees, 2023106

Source for Williamson County: Census County Business Patterns, NAICS 238160.

Nearby counties

The closest counties that have a risk page, by distance between county centres. Loss is per $1 million of buildings; the columns marked "times here" divide the neighbour's loss by Williamson County's.

CountyMilesOverallHail lossHail, times hereWind lossWind, times hereNOAA hail reports
Rutherford County, TN28 Relatively Moderate $5.611.07$5.541.1948
Sumner County, TN46 Relatively Moderate $458.52$153.1851
Montgomery County, TN49 Relatively Moderate $489.14$469.7620
Putnam County, TN84 Relatively Low $407.55$449.4435
Hamilton County, TN106 Relatively Moderate $112.18$7.241.5520
Madison County, TN110 Relatively Moderate $1.830.35$7.271.5654

More Tennessee counties, nearest first

All 194 counties, with a filter by state and sorting

Cities and ZIP areas in Williamson County

1 city in this county is on PickARoofer. ZIP Code Tabulation Areas are Census shapes that approximate ZIP codes; where we have a city’s ZIPs, the share is the part of each area’s land that lies in this county. 9 such areas have more than half their land here.

CityZIP areas (share of land in the county)Pages
Franklin 37064 (99%), 37072 (0%), 37074 (0%), 37069 (100%) Roofers

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Questions

How high is storm risk in Williamson County?

FEMA's National Risk Index gives Williamson County an overall score of 85.15 (Relatively Moderate), 468th of 3,144. Hail scores 41.86 (Relatively Low), strong wind 89.12 (Relatively High) and tornado 88.87 (Relatively Moderate).

In Williamson County, how many hail reports has NOAA logged?

A report is one entry for one storm in one county, so counts follow where people live as well as where hail fell. NOAA has 105 for Williamson County between 2014 and June 2026, on 23 days with hail of 1 inch or more; the largest stone was 3 inches.

What do hail and wind cost a home in Williamson County each year, on average?

Applying FEMA's county rates to its median home value of $673,700: FEMA's estimate is about $3.53 a year for hail and $3.15 for wind, before any deductible, against $15 and $14 at the U.S. median county rates. This is an average over many years and all buildings, not a prediction for one roof; one bad storm costs far more than the average year.

How does Williamson County compare with the rest of Tennessee?

Per $1 million of buildings Williamson County loses $5.23 to hail a year, against $12 in the median county of the state. Among 95 rated counties it is 30th for hail, 7th for strong wind and 14th for tornado.

How old are the roofs in Williamson County?

The median home was built in 2001, 25 years ago, and 47.7% of the 94,418 housing units in Williamson County date from before 2000. Asphalt shingles are rated 15 to 20 years (3-tab) or 25 to 30 years (architectural), so an original 3-tab roof is past its rated life and an architectural one is inside it. The Census does not record when a roof was replaced.

What does expected annual loss mean?

It is FEMA's estimate of the average yearly loss from a hazard, in dollars, summed over the county. It is built for comparing counties at planning level, not for pricing one house.

Does a high rating mean my roof will be damaged?

No. The index compares counties and cannot say what will happen on your street. After a storm, a roof inspection is the only way to know.

Sources for Williamson County: FEMA National Risk Index, version December 2025, retrieved October 8, 2026; NOAA Storm Events Database hail reports for Williamson County; Census Bureau ZCTA-to-county relationship file (2020); Census ACS and Building Permits Survey, homes in Williamson County; Census County Business Patterns, roofing firms in Williamson County. Planning-level information about Williamson County, not an inspection and not insurance advice.

This product uses the Federal Emergency Management Agency's National Risk Index dataset but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).