The most recent reported hail day was 2026-04-14, 108 days ago. Grundy County is hit in most years. The largest stone on record here is 1.75 inches, a golf ball and 1.8 times the National Weather Service's 1 inch severe criterion, reported on 2026-04-14 near Wellsburg.
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 Wellsburg. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls Grundy 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 16 separate hail days here since 2010 -- 0.9 a year over 17 years of record. They carry 19 reports in total: most hail days here are logged from a single spot. 6 of those 17 years produced none at all. The busiest single year was 2018, with 3 hail days. The last five years track the long-run rate, with 6 days since 2022.
No stone of 2 inches or more has ever been reported in Grundy County: all 16 hail days on record topped out below that. Golf-ball size is rarer still: 1.75 inches or more on 2 of the 16 days.
Across the whole of Iowa, see the Iowa hail map and history.
Reports cluster nearest Dike -- 6 of the county's 16 hail days -- then Holland (3), Wellsburg (2), Conrad (2) and Parkersburg (2).
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Dike | 4 | 1.75″ |
| Conrad | 2 | 1.00″ |
| 1 NW Holland | 1 | 1.75″ |
| 1 S Wellsburg | 1 | 1.75″ |
| 1 Ene Holland | 1 | 1.50″ |
The season runs April through July: 13 of the 16 hail days on record fall in those 4 months (81%). April is the single busiest month, with 5 of them (31%). 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 | 5 |
| May | 2 |
| June | 4 |
| July | 2 |
| August | 2 |
| September | 1 |
That day put 3 reports on the map, the biggest 1.75 inches near Wellsburg. 1 hail day has already been reported this year.
| Date | Max hail | Reports |
|---|---|---|
| 2026-04-14 | 1.75″ | 3 |
| 2025-09-22 | 1.00″ | 1 |
| 2024-05-19 | 1.00″ | 1 |
| 2023-07-28 | 1.00″ | 1 |
| 2022-08-19 | 1.50″ | 2 |
| 2022-06-14 | 1.00″ | 1 |
| 2020-07-11 | 1.00″ | 1 |
| 2019-06-28 | 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 1.75 inches, which is the red band. Look up a street address with the hail history by address tool.
The nearest counties with a page of their own: Black Hawk County (23 hail days), Hardin County (16) and Tama County (19). Grundy County sits in between.
Black Hawk County · Hardin County · Tama 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, Grundy County, Iowa only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.