Clayton County, Iowa Hail Map & History
Clayton County was hit as recently as 2026-09-04, 10 days ago. Clayton County has recorded hail in nearly every year on the archive. 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 2026-04-14 near Monona.
Colored swath = NOAA MRMS radar-estimated hail size; dots = NOAA SPC reports in Iowa. Radar-indicated, not a guarantee of damage.
The last hail here fell on 2026-09-04, around Monona. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls Clayton 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 ->How often it hails in Clayton County
NOAA's Storm Prediction Center has logged 23 separate hail days here since 2010 -- 1.4 a year over 17 years of record. Those days carry 45 separate reports between them, two or three on a typical one. 2 of those 17 years produced none at all. The busiest single year was 2017, with 4 hail days. The last five years track the long-run rate, with 7 days since 2022.
Most hail here stays under 2 inches: only 1 of the 23 days on record passed it, 4%, the last on 2026-04-14. They land in the same month as everything else, April. 10 of the 23 days reached golf-ball size, 1.75 inches or bigger.
Across the whole of Iowa, see the Iowa hail map and history.
Hardest-hit places in Clayton County
Reports cluster nearest Strawberry Point -- 5 of the county's 23 hail days -- then Elkader (5), Monona (4), Guttenberg (4) and Osterdock (3). Beyond those, NOAA names Garnavillo, Osborne, Elkport, Mcgregor and North Buena Vista on more than one hail day apiece.
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Strawberry Point | 5 | 1.75″ |
| Monona | 4 | 2.50″ |
| Elkader | 3 | 1.00″ |
| Osborne | 2 | 1.50″ |
| Mcgregor | 2 | 1.00″ |
When it hails in Clayton County
The season runs March through July: 20 of the 23 hail days on record fall in those 5 months (87%). April is the single busiest month, with 7 of them (30%). That peak sits inside the window rather than at either end. Hail has also been reported in September, outside that window. Reports span 6 of the 12 calendar months; the other 6 have never produced one.
| Month | Hail days |
|---|---|
| March | 2 |
| April | 7 |
| May | 2 |
| June | 3 |
| July | 6 |
| September | 3 |
Recent Clayton County hail days
That day put 2 reports on the map, the biggest 1.5 inches near Monona. 3 hail days have already been reported this year.
| Date | Max hail | Reports |
|---|---|---|
| 2026-09-04 | 1.50″ | 2 |
| 2026-07-02 | 1.00″ | 2 |
| 2026-04-14 | 2.50″ | 1 |
| 2025-04-18 | 1.00″ | 1 |
| 2025-04-17 | 1.50″ | 4 |
| 2023-04-04 | 1.00″ | 1 |
| 2022-07-04 | 1.00″ | 2 |
| 2020-03-28 | 1.00″ | 2 |
How to read the Clayton County map
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.
Nearby counties
The nearest counties with a page of their own, over the state line included: Delaware County (17 hail days), Fayette County (23), Buchanan County (21) and Grant County, Wisconsin (28). Clayton County sits in between.
Delaware County · Fayette County · Buchanan County · Grant County, Wisconsin
Back to the Iowa hail map or the U.S. hail map.
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Data & method: NOAA/NWS Storm Prediction Center reports + NOAA MRMS MESH radar, Clayton County, Iowa only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.