The most recent reported hail day was 2025-05-16 -- 1 year ago, with nothing reported since. Williamson County is hit in most years. The largest stone on record here is 3 inches, a teacup and 3 times the National Weather Service's 1 inch severe criterion, reported on 2023-06-30 near Energy.
Colored swath = NOAA MRMS radar-estimated hail size; dots = NOAA SPC reports in Illinois. Radar-indicated, not a guarantee of damage.
The last hail here fell on 2025-05-16, around Cambria. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls Williamson County addresses inside a hail swath above your size threshold into a door-knock list you can export, scoped to your approved markets.
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See call-center options ->NOAA's Storm Prediction Center has logged 24 separate hail days here since 2010 -- 1.4 a year over 17 years of record. Those days carry 52 separate reports between them, two or three on a typical one. 5 of those 17 years produced none at all. The busiest single year was 2025, with 4 hail days. The last five years have run hotter than the long-run rate: 11 days since 2022, against 1.1 a year before that.
4 of the 24 days reached 2 inches or more -- 17%, or about one hail day in 6, the last on 2024-05-26. Those big days do not follow the county's usual calendar: most of them fall in February, not May. 7 of the 24 days reached golf-ball size, 1.75 inches or bigger.
Across the whole of Illinois, see the Illinois hail map and history.
Reports cluster nearest Marion -- 8 of the county's 24 hail days -- then Carterville (6), Johnston City (4), Crainville (2) and Hurst (2). Beyond those, NOAA names Goreville, Creal Springs and Herrin on more than one hail day apiece.
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Marion | 6 | 1.75″ |
| Carterville | 5 | 1.75″ |
| Johnston City | 4 | 3.00″ |
| 2 WNW Marion | 2 | 1.75″ |
| Hurst | 2 | 1.50″ |
The season runs March through July: 23 of the 24 hail days on record fall in those 5 months (96%). May is the single busiest month, with 7 of them (29%). That peak sits inside the window rather than at either end. Hail has also been reported in February, outside that window. Reports span 6 of the 12 calendar months; the other 6 have never produced one.
| Month | Hail days |
|---|---|
| February | 1 |
| March | 4 |
| April | 6 |
| May | 7 |
| June | 2 |
| July | 4 |
That day put 2 reports on the map, the biggest 1.75 inches near Cambria. No hail day has been reported here yet this year.
| Date | Max hail | Reports |
|---|---|---|
| 2025-05-16 | 1.75″ | 2 |
| 2025-05-01 | 1.00″ | 3 |
| 2025-04-02 | 1.25″ | 1 |
| 2025-03-30 | 1.50″ | 1 |
| 2024-05-26 | 2.00″ | 2 |
| 2024-05-08 | 1.75″ | 2 |
| 2024-04-02 | 1.00″ | 1 |
| 2023-07-02 | 1.25″ | 1 |
The colored swath is NOAA's MRMS radar estimate of the largest hail per ~1 km cell; the dots are SPC ground reports. Yellow is about an inch, red 1.5 to 2″, purple 2″ and up (hail size vs roof damage). On this county's worst day the reports reached 3 inches, which is the purple band. Look up a street address with the hail history by address tool.
The nearest counties with a page of their own: Franklin County (24 hail days), Jackson County (26) and Johnson County (20). Williamson County sits in between.
Franklin County · Jackson County · Johnson County
Back to the Illinois hail map or the U.S. hail map.
Data & method: NOAA/NWS Storm Prediction Center reports + NOAA MRMS MESH radar, Williamson County, Illinois only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.