Grundy County, IA hail & severe wind history
70 storm reports on file for Grundy County between 2010-04-06 and 2025-09-22 — 27 hail and 43 severe thunderstorm wind. That averages 4.4 reports a year, and Jun is the busiest month.
At a glance
- Most recent hail report: Sep 22, 2025 — 1" (quarter), 2.76 mi S of Dike.
- Hail was reported on 21 days since 2010 — about 1.4 hail days a year.
- Largest hail on record: 1.75" (golf ball) on Apr 6, 2010.
- Grundy County has more hail reports than 6% of the 99 Iowa counties we cover.
Search every Grundy 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 Grundy County storm reports…
Worst storm days in Grundy County
| Date | Reports that day | Largest hail | Peak gust |
|---|---|---|---|
| 2017-03-06 | 4 | — | 75 mph |
| 2018-06-06 | 3 | 1" (quarter) | 64 mph |
| 2013-04-29 | 3 | 1" (quarter) | — |
| 2014-06-30 | 3 | 0.88" (nickel) | 70 mph |
| 2014-08-31 | 3 | — | 70 mph |
| 2013-06-24 | 3 | — | 70 mph |
| 2010-04-06 | 2 | 1.75" (golf ball) | — |
| 2022-08-19 | 2 | 1.5" (ping pong ball) | — |
| 2013-04-09 | 2 | 1" (quarter) | — |
| 2025-07-03 | 2 | — | 60 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.
When does hail hit Grundy County?
Across 15 years of records, June produced the most reports (21), followed by the months either side of it. Monthly totals:
| Month | Reports | Share |
|---|---|---|
| January | 0 | 0.0% |
| February | 0 | 0.0% |
| March | 6 | 8.6% |
| April | 8 | 11.4% |
| May | 13 | 18.6% |
| June | 21 | 30.0% |
| July | 8 | 11.4% |
| August | 10 | 14.3% |
| September | 4 | 5.7% |
| October | 0 | 0.0% |
| November | 0 | 0.0% |
| December | 0 | 0.0% |
Neighboring counties
Counties that share a border with Grundy County (U.S. Census county adjacency), where we have storm records:
| County | Storm reports | Largest hail |
|---|---|---|
| Black Hawk County, IA | 210 | 3.5" |
| Marshall County, IA | 149 | 1.75" |
| Butler County, IA | 148 | 2.5" |
| Hardin County, IA | 116 | 1.75" |
| Franklin County, IA | 111 | 2" |
| Tama County, IA | 96 | 2" |
Common questions about hail in Grundy County
- How often does it hail in Grundy County?
- Hail was reported on 21 separate days between 2010 and 2025, about 1.4 days a year, with June the busiest month for storm reports. 18 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 19075). 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.