The most recent reported hail day was 2026-04-14, 108 days ago. Johnson County is hit in most years. 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 2026-03-10 near West Branch.
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 2026-04-14, around Iowa City. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls Johnson 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 33 separate hail days here since 2010 -- 1.9 a year over 17 years of record. Those days carry 86 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 2024, with 5 hail days. The last five years have run hotter than the long-run rate: 15 days since 2022, against 1.5 a year before that.
Most hail here stays under 2 inches: only 2 of the 33 days on record passed it, 6%, the last on 2026-03-10. Those big days do not follow the county's usual calendar: most of them fall in March, not April. 9 of the 33 days reached golf-ball size, 1.75 inches or bigger.
Across the whole of Iowa, see the Iowa hail map and history.
Reports cluster nearest Iowa City -- 8 of the county's 33 hail days -- then Coralville (7), North Liberty (6), Hills (6) and Williamstown (4). Beyond those, NOAA names Downey, University Heights, Tiffin, West Branch, Iowa City Municipal, Se Iowa City and Solon on more than one hail day apiece.
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Iowa City | 6 | 1.75″ |
| Coralville | 3 | 1.50″ |
| 2 Sse Hills | 3 | 1.00″ |
| 1 Ene North Liberty | 2 | 1.75″ |
| 2 Nnw North Liberty | 2 | 1.75″ |
The season runs March through July: 28 of the 33 hail days on record fall in those 5 months (85%). April is the single busiest month, with 10 of them (30%). That peak sits inside the window rather than at either end. Hail has also been reported in February, August, September and October, outside that window. January, November and December are the only months that have never produced a reported hail day.
| Month | Hail days |
|---|---|
| February | 1 |
| March | 3 |
| April | 10 |
| May | 8 |
| June | 3 |
| July | 4 |
| August | 1 |
| September | 1 |
| October | 2 |
That day put 5 reports on the map, the biggest 1.5 inches near Iowa City. 4 hail days have already been reported this year.
| Date | Max hail | Reports |
|---|---|---|
| 2026-04-14 | 1.50″ | 5 |
| 2026-04-02 | 1.75″ | 1 |
| 2026-03-15 | 1.50″ | 1 |
| 2026-03-10 | 2.75″ | 11 |
| 2025-07-10 | 1.00″ | 1 |
| 2024-10-24 | 1.00″ | 1 |
| 2024-06-25 | 1.75″ | 3 |
| 2024-05-24 | 1.00″ | 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 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: Washington County (24 hail days), Iowa County (22) and Linn County (38). Johnson County sits in between.
Washington County · Iowa County · Linn County
Back to the Iowa hail map or the U.S. hail map.
Data & method: NOAA/NWS Storm Prediction Center reports + NOAA MRMS MESH radar, Johnson County, Iowa only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.