Hail history for O'Brien County, Iowa
Every NOAA hail report filed in O'Brien County since 1965, with preliminary National Weather Service reports to November 3, 2026.
Readout · O'Brien County
- Last hail
- Jun 28, 2026
- 1.00 in, quarter size
- Hail days, last 5 years
- 21
- since Nov 3, 2021 · 39 reports
- Largest ever
- 4.00 in
- grapefruit · Jul 9, 2009
209 reports on 105 days since 1965 · #19 of 100 Iowa counties
Hail map · O'Brien County
- Under 1 in
- 1–1.75 in
- 1.75–2.5 in
- 2.5–4 in
- 4 in +
- No size
For homeowners
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What the record says about O'Brien County
The latest hail report in O'Brien County is from June 28, 2026, 1.00 in (quarter size). Since November 3, 2021 there have been 21 separate hail days; the biggest stones in that time were 2.00 in on September 22, 2025.
Over the 20 years 2006–2025, O'Brien County logged 85 reports on 47 hail days, about 4.3 reports a year. That is 15% more than the median Iowa county (3.7 a year) and ranks #19 of 100 Iowa counties for all-time reports. O'Brien County holds 1% of all 16,032 hail reports in Iowa.
5% of reports with a size were 2 inches (hen egg) or larger, against 7% for the median Iowa county. The largest hail on record here is 4.00 in (grapefruit) on July 9, 2009 near 1.51 E Sheldon.
Reports were up 18% in 2016–2025 (46) compared with 2006–2015 (39). The busiest year was 2004, with 38 reports on 9 days. Hail here peaks in May (23% of reports); 52% fall between April and June.
Reports a year 2006–2025 average
- O'Brien County 4.3
- Median Iowa county 3.7
Hail days 2006–2025
- O'Brien County 47
- Median Iowa county 39.5
Share 2 in or larger of sized reports
- O'Brien County 5%
- Median Iowa county 7%
Hail over time
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | 7 | 3 | 1 | 11 | |||||||||
| 2025 | 1 | 1 | 6 | 8 | |||||||||
| 2024 | 3 | 5 | 1 | 2 | 11 | ||||||||
| 2023 | 1 | 5 | 6 | ||||||||||
| 2022 | 1 | 1 | 1 | 3 | |||||||||
| 2021 | 0 | ||||||||||||
| 2020 | 3 | 3 | |||||||||||
| 2019 | 1 | 1 | |||||||||||
| 2018 | 2 | 3 | 5 | ||||||||||
| 2017 | 1 | 1 | 6 | 8 |
Hail days since Nov 3, 2021
| Date | Reports | Largest | Storm page |
|---|---|---|---|
| Jun 28, 2026 | 1 | 1.00 in | — |
| May 25, 2026 | 1 | 1.25 in | — |
| May 18, 2026 | 1 | 1.00 in | — |
| May 17, 2026 | 1 | 1.75 in | — |
| Apr 13, 2026 | 7 | 1.75 in | — |
| Sep 22, 2025 | 4 | 2.00 in | — |
| Sep 16, 2025 | 2 | 1.75 in | — |
| Aug 6, 2025 | 1 | 0.75 in | — |
| Apr 17, 2025 | 1 | 1.50 in | — |
| Jul 10, 2024 | 2 | 2.00 in | — |
| Jun 15, 2024 | 1 | 0.88 in | — |
| May 20, 2024 | 5 | 1.75 in | — |
| Apr 30, 2024 | 2 | 0.75 in | — |
| Apr 26, 2024 | 1 | 1.00 in | — |
| Jul 26, 2023 | 2 | 1.75 in | — |
| Jul 13, 2023 | 1 | 1.50 in | — |
| Jul 10, 2023 | 2 | 1.75 in | — |
| May 31, 2023 | 1 | 0.75 in | — |
| Aug 18, 2022 | 1 | 1.00 in | — |
| May 30, 2022 | 1 | 1.25 in | — |
| Apr 23, 2022 | 1 | 1.00 in | — |
Largest hail on record
| Date | Size | Location | Damage | Time · source |
|---|---|---|---|---|
| Jul 9, 2009 | 4.00 ingrapefruit | 1.51 E Sheldon | $2.0 million | 18:35 local · NCEI |
| Jun 28, 1990 | 3.00 inteacup | — | — | 02:35 local · NCEI |
| Jun 5, 1999 | 2.75 inbaseball | Primghar | — | 17:04 local · NCEI |
| Jun 5, 1999 | 2.75 inbaseball | Germantown | — | 16:35 local · NCEI |
| Aug 7, 1984 | 2.75 inbaseball | — | — | 14:22 local · NCEI |
Sizes filed before 1996 are often rough estimates (round numbers like 7.00 or 8.00 in) without an exact spot; they are shown as NOAA filed them.
Size of every report
- Under 1 in 85 41%
- 1–2 in 113 54%
- 2 in + 11 5%
Most recent reports
| Date | Size | Location | Time · source |
|---|---|---|---|
| Jun 28, 2026 | 1.00 inquarter | 0.86 NE Sanborn | 05:09 local · NCEI |
| May 25, 2026 | 1.25 inhalf dollar | 0.86 NE Sanborn | 00:37 local · NCEI |
| May 18, 2026 | 1.00 inquarter | 0.86 NE Sanborn | 16:51 local · NCEI |
| May 17, 2026 | 1.75 ingolf ball | 2.81 S Sanborn | 19:09 local · NCEI |
| Apr 13, 2026 | 1.50 inping pong ball | 0.5 E Sanborn | 17:44 local · NCEI |
| Apr 13, 2026 | 1.25 inhalf dollar | 0.5 E Sanborn | 17:41 local · NCEI |
| Apr 13, 2026 | 1.00 inquarter | 2.81 S Sanborn | 17:40 local · NCEI |
| Apr 13, 2026 | 1.50 inping pong ball | 0.5 E Sanborn | 17:40 local · NCEI |
| Apr 13, 2026 | 1.75 ingolf ball | 2.87 WSW Sanborn | 17:34 local · NCEI |
| Apr 13, 2026 | 1.00 inquarter | 0.69 N Primghar | 17:28 local · NCEI |
| Apr 13, 2026 | 1.75 ingolf ball | 2.14 WSW Germantown | 17:08 local · NCEI |
| Sep 22, 2025 | 1.00 inquarter | 2.88 WSW Primghar | 18:40 local · NCEI |
Cities and towns in O'Brien County
Smaller places with fewer than 10 reports
These places have too few reports for a page of their own, so their record lives here.
| Place | Reports | Hail days | Latest |
|---|---|---|---|
| Calumet | 2 | 2 | Jul 13, 2004 |
Questions about hail in O'Brien County
How often does it hail in O'Brien County, Iowa?
209 hail reports have been logged in O'Brien County since 1965. Over the 20 years 2006–2025 that averages 4.3 reports a year. That ranks #19 of 100 Iowa counties by number of reports.
When is hail season in O'Brien County?
Most reports come in May, July, June. May alone accounts for 23% of all reports.
What is the largest hail recorded in O'Brien County?
4.00 in (grapefruit size) on July 9, 2009 near 1.51 E Sheldon. 5% of reports here were 2 inches or larger.
When did it last hail in O'Brien County?
The most recent report in this data is from June 28, 2026 (1.00 in). Final NOAA data runs to July 31, 2026; preliminary NWS reports run to November 3, 2026.
How many hail storms has O'Brien County had in the last five years?
21 separate days with hail reports since November 3, 2021, adding up to 39 reports. The most recent was June 28, 2026.
Where does this hail data come from?
Hail reports come from the NOAA NCEI Storm Events Database, which the National Weather Service compiles from spotter, public, law enforcement and media reports. Recent days use preliminary NWS Local Storm Reports via the Iowa Environmental Mesonet until NOAA publishes final data. Only reported hail is counted, so areas with fewer people tend to have fewer reports.