Brown County was hit as recently as 2026-07-24, 7 days ago. Brown County is hit in most years, and usually several times over. The largest stone on record here is 4.25 inches and 4.2 times the National Weather Service's 1 inch severe criterion, reported on 2010-07-17 near Westport.
Colored swath = NOAA MRMS radar-estimated hail size; dots = NOAA SPC reports in South Dakota. Radar-indicated, not a guarantee of damage.
The last hail here fell on 2026-07-24, around Westport. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls Brown 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 58 separate hail days here since 2010 -- 3.4 a year over 17 years of record. Those days carry 148 separate reports between them, two or three on a typical one. No year since 2010 has gone by without at least one. The busiest single year was 2022, with 6 hail days. The last five years track the long-run rate, with 16 days since 2022.
9 of the 58 days reached 2 inches or more -- 16%, or about one hail day in 6, the last on 2026-07-24. Those big days do not follow the county's usual calendar: most of them fall in July, not June. 18 of the 58 days reached golf-ball size, 1.75 inches or bigger.
Across the whole of South Dakota, see the South Dakota hail map and history.
Reports cluster nearest Aberdeen -- 14 of the county's 58 hail days -- then Groton (11), Frederick (8), Westport (6) and Barnard (6). Beyond those, NOAA names Columbia, Bath, Warner, Claremont, Houghton, Richmond Lake Rec Area, Hecla, Wetonka and Elm Lake on more than one hail day apiece.
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Aberdeen | 7 | 1.25″ |
| Bath | 5 | 1.75″ |
| Groton | 5 | 1.75″ |
| Richmond Lake Rec Area | 4 | 2.75″ |
| Warner | 4 | 1.75″ |
The season runs May through August: 51 of the 58 hail days on record fall in those 4 months (88%). June is the single busiest month, with 17 of them (29%). That peak sits inside the window rather than at either end. Hail has also been reported in April and September, outside that window. Reports span 6 of the 12 calendar months; the other 6 have never produced one.
| Month | Hail days |
|---|---|
| April | 4 |
| May | 6 |
| June | 17 |
| July | 13 |
| August | 15 |
| September | 3 |
That day put 5 reports on the map, the biggest 2 inches near Westport. 2 hail days have already been reported this year.
| Date | Max hail | Reports |
|---|---|---|
| 2026-07-24 | 2.00″ | 5 |
| 2026-06-29 | 1.00″ | 1 |
| 2025-08-05 | 1.50″ | 2 |
| 2024-07-31 | 1.00″ | 1 |
| 2024-07-09 | 1.25″ | 1 |
| 2024-07-06 | 1.00″ | 1 |
| 2024-06-02 | 2.75″ | 6 |
| 2024-05-23 | 1.25″ | 3 |
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 4.25 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, over the state line included: Marshall County (18 hail days), Day County (44), McPherson County (42) and Dickey County, North Dakota (29). Brown County takes more hail than any of them.
Marshall County · Day County · McPherson County · Dickey County, North Dakota
Back to the South Dakota hail map or the U.S. hail map.
Data & method: NOAA/NWS Storm Prediction Center reports + NOAA MRMS MESH radar, Brown County, South Dakota only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.