The most recent reported hail day was 2026-04-17, 105 days ago. Walworth County is hit in most years. The largest stone on record here is 2.5 inches, a tennis ball and 2.5 times the National Weather Service's 1 inch severe criterion, reported on 2018-05-02 near Williams Bay.
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 2026-04-17, around Palmyra. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls Walworth 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 27 separate hail days here since 2010 -- 1.6 a year over 17 years of record. Those days carry 60 separate reports between them, two or three on a typical one. 3 of those 17 years produced none at all. The busiest single year was 2017, with 5 hail days. The last five years track the long-run rate, with 7 days since 2022.
3 of the 27 days reached 2 inches or more -- 11%, or about one hail day in 9, the last on 2026-04-02. Those big days do not follow the county's usual calendar: most of them fall in May, not April.
Across the whole of Wisconsin, see the Wisconsin hail map and history.
Reports cluster nearest Elkhorn -- 7 of the county's 27 hail days -- then Lake Geneva (6), Whitewater (4), Delavan (4) and Williams Bay (3). Beyond those, NOAA names East Troy, Pell Lake, Genoa City and Palmyra on more than one hail day apiece.
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Elkhorn | 5 | 1.00″ |
| Delavan | 3 | 1.50″ |
| East Troy | 2 | 2.00″ |
| Genoa City | 2 | 1.75″ |
| Williams Bay | 2 | 1.50″ |
The season runs April through July: 22 of the 27 hail days on record fall in those 4 months (81%). April is the single busiest month, with 6 of them (22%). That peak opens the window: the season starts at its worst and eases off from there. Hail has also been reported in August and September, outside that window. Reports span 6 of the 12 calendar months; the other 6 have never produced one.
| Month | Hail days |
|---|---|
| April | 6 |
| May | 5 |
| June | 6 |
| July | 5 |
| August | 3 |
| September | 2 |
That day put 1 report on the map, the biggest 1 inch near Palmyra. 4 hail days have already been reported this year.
| Date | Max hail | Reports |
|---|---|---|
| 2026-04-17 | 1.00″ | 1 |
| 2026-04-15 | 1.00″ | 1 |
| 2026-04-03 | 1.00″ | 1 |
| 2026-04-02 | 2.00″ | 2 |
| 2025-05-15 | 2.00″ | 6 |
| 2023-04-04 | 1.00″ | 1 |
| 2022-07-23 | 1.00″ | 1 |
| 2021-09-07 | 1.50″ | 7 |
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 2.5 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: Racine County (16 hail days), Waukesha County (33), Rock County (32) and McHenry County, Illinois (35). Walworth County sits in between.
Racine County · Waukesha County · Rock County · McHenry 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, Walworth County, Wisconsin only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.