Johnson County, IA hail & severe wind history
295 storm reports on file for Johnson County between 2010-04-05 and 2026-06-17 — 138 hail and 157 severe thunderstorm wind. That averages 17.4 reports a year, and May is the busiest month.
At a glance
- Most recent hail report: Apr 14, 2026 — 1.5" (ping pong ball), 0.86 mi SE of Iowa City.
- Hail was reported on 55 days since 2010 — about 3.4 hail days a year.
- Largest hail on record: 2.75" (baseball) on Mar 10, 2026.
- Johnson County has more hail reports than 95% of the 99 Iowa counties we cover.
Search every Johnson County report
Check a single date first, or filter the full record below — pick a year, narrow to a month, or drag the hail-size slider to see only the larger stones (1", quarter size, is the National Weather Service severe threshold).
Loading Johnson County storm reports…
Worst storm days in Johnson County
| Date | Reports that day | Largest hail | Peak gust |
|---|---|---|---|
| 2023-05-07 | 20 | 1.5" (ping pong ball) | 75 mph |
| 2026-03-10 | 12 | 2.75" (baseball) | — |
| 2017-02-28 | 11 | 1.5" (ping pong ball) | — |
| 2020-07-11 | 10 | 1.75" (golf ball) | — |
| 2014-06-16 | 9 | 1.75" (golf ball) | 69 mph |
| 2024-05-24 | 8 | 1" (quarter) | 75 mph |
| 2021-12-15 | 7 | — | 70 mph |
| 2024-06-25 | 6 | 1.75" (golf ball) | 68 mph |
| 2011-05-22 | 6 | 1.75" (golf ball) | — |
| 2024-04-16 | 6 | 1" (quarter) | 75 mph |
Reports by year
Report counts are driven partly by how many people were around to report a storm, so recent years tend to look busier than the early 2010s. Treat the trend as a reporting trend, not purely a weather trend.
Notable large-hail events (2" and up)
| Date | Size | Near | What was reported |
|---|---|---|---|
| 2026-03-10 | 2.5" tennis ball | 2.49 mi SW of University Hgts | No narrative filed |
| 2026-03-10 | 2.75" baseball | 3.49 mi S of Oasis | No narrative filed |
| 2011-04-03 | 2" hen egg | 1.47 mi SSW of Swisher | Two inch diameter hail fell 1 mile southwest of Swisher, IA at 651 pm CDT April 3. |
When does hail hit Johnson County?
Across 16 years of records, May produced the most reports (70), followed by the months either side of it. Monthly totals:
| Month | Reports | Share |
|---|---|---|
| January | 0 | 0.0% |
| February | 14 | 4.7% |
| March | 23 | 7.8% |
| April | 45 | 15.3% |
| May | 70 | 23.7% |
| June | 44 | 14.9% |
| July | 47 | 15.9% |
| August | 24 | 8.1% |
| September | 9 | 3.1% |
| October | 6 | 2.0% |
| November | 6 | 2.0% |
| December | 7 | 2.4% |
Neighboring counties
Counties that share a border with Johnson County (U.S. Census county adjacency), where we have storm records:
| County | Storm reports | Largest hail |
|---|---|---|
| Linn County, IA | 550 | 2.75" |
| Benton County, IA | 265 | 2" |
| Cedar County, IA | 184 | 2.75" |
| Muscatine County, IA | 159 | 2" |
| Washington County, IA | 141 | 2.5" |
| Iowa County, IA | 132 | 2.75" |
| Louisa County, IA | 62 | 2.75" |
Common questions about hail in Johnson County
- How often does it hail in Johnson County?
- Hail was reported on 55 separate days between 2010 and 2026, about 3.4 days a year, with May the busiest month for storm reports. 86 reports were quarter size (1") or larger.
- Does a report here mean hail hit my street?
- Not necessarily. Each report is one observation tied to a nearby landmark, and a county can be large. Storms also go unreported where few people live. Use the date check above to see what was reported nearby, and treat it as a starting point.
- How big is a 1.75" hailstone?
- Forecasters describe hail by everyday objects: 1" is a quarter, 1.75" a golf ball, 2.75" a baseball. The sizes in these reports are estimates made by the person reporting, not lab measurements.
- Where do I get the official record?
- All reports here come from the NOAA NCEI Storm Events Database, which you can search directly. For anything formal, use NOAA’s own records rather than this page.
Look up another place
About these numbers
Every row above is a report filed with the National Weather Service and archived in the NOAA NCEI Storm Events Database (FIPS 19103). Reports are eyewitness, trained-spotter and damage-survey observations, so they cluster near roads and towns and miss storms over empty country. Hail sizes are estimates. Damage figures are preliminary as filed and are never revised in this archive. Use this page for background, not for an insurance claim, a legal filing, or a roof assessment — for those, get the official record from NOAA directly.