Rock County was hit as recently as 2026-06-24, 37 days ago. Rock County has recorded hail in nearly every year on the archive. The largest stone on record here is 2.75 inches, a baseball and 2.8 times the National Weather Service's 1 inch severe criterion, reported on 2025-04-18 near Evansville.
Colored swath = NOAA MRMS radar-estimated hail size; dots = NOAA SPC reports in Wisconsin. Radar-indicated, not a guarantee of damage.
The last hail here fell on 2026-06-24, around Milton. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls Rock 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 32 separate hail days here since 2010 -- 1.9 a year over 17 years of record. Those days carry 74 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 2026, with 4 hail days. The last five years track the long-run rate, with 12 days since 2022.
6 of the 32 days reached 2 inches or more -- 19%, or about one hail day in 5, the last on 2026-04-17. They land in the same month as everything else, April. Golf-ball size is rarer still: 1.75 inches or more on 7 of the 32 days.
Across the whole of Wisconsin, see the Wisconsin hail map and history.
Reports cluster nearest Janesville -- 9 of the county's 32 hail days -- then Beloit (8), Edgerton (6), Evansville (5) and Milton (5). Beyond those, NOAA names Orfordville and Clinton on more than one hail day apiece.
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Beloit | 7 | 1.75″ |
| Edgerton | 4 | 2.75″ |
| Evansville | 4 | 2.00″ |
| Milton | 3 | 1.75″ |
| 1 WNW Janesville | 3 | 1.25″ |
The season runs March through August: 28 of the 32 hail days on record fall in those 6 months (88%). April is the single busiest month, with 6 of them (19%). That peak sits inside the window rather than at either end. Hail has also been reported in September and October, outside that window. Reports span 8 of the 12 calendar months; the other 4 have never produced one.
| Month | Hail days |
|---|---|
| March | 3 |
| April | 6 |
| May | 6 |
| June | 3 |
| July | 4 |
| August | 6 |
| September | 3 |
| October | 1 |
That day put 1 report on the map, the biggest 1.25 inches near Milton. 4 hail days have already been reported this year.
| Date | Max hail | Reports |
|---|---|---|
| 2026-06-24 | 1.25″ | 1 |
| 2026-04-17 | 2.00″ | 5 |
| 2026-04-02 | 1.50″ | 2 |
| 2026-03-10 | 1.00″ | 1 |
| 2025-08-16 | 1.50″ | 7 |
| 2025-04-18 | 2.75″ | 10 |
| 2025-04-17 | 2.00″ | 1 |
| 2024-06-25 | 1.25″ | 5 |
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 2.75 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: Green County (18 hail days), Jefferson County (24), Walworth County (27) and Winnebago County, Illinois (41). Rock County sits in between.
Green County · Jefferson County · Walworth County · Winnebago County, Illinois
Back to the Wisconsin hail map or the U.S. hail map.
Data & method: NOAA/NWS Storm Prediction Center reports + NOAA MRMS MESH radar, Rock County, Wisconsin only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.