The most recent reported hail day was 2025-06-27, 399 days ago. Oliver County is hit in most years. The largest stone on record here is 3.5 inches and 3.5 times the National Weather Service's 1 inch severe criterion, reported on 2025-06-27 near Hannover.
Colored swath = NOAA MRMS radar-estimated hail size; dots = NOAA SPC reports in North Dakota. Radar-indicated, not a guarantee of damage.
The last hail here fell on 2025-06-27, around Hannover. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls Oliver 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 24 separate hail days here since 2010 -- 1.4 a year over 17 years of record. Those days carry 46 separate reports between them, two or three on a typical one. 4 of those 17 years produced none at all. The busiest single year was 2019, with 4 hail days. The last five years track the long-run rate, with 6 days since 2022.
4 of the 24 days reached 2 inches or more -- 17%, or about one hail day in 6, the last on 2025-06-27. Those big days do not follow the county's usual calendar: most of them fall in June, not July. 7 of the 24 days reached golf-ball size, 1.75 inches or bigger.
Across the whole of North Dakota, see the North Dakota hail map and history.
Reports cluster nearest Hannover -- 14 of the county's 24 hail days -- then Center (9), Beulah (2), Price (2) and Hazen (2). That one town is named on 58% of them.
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Center | 7 | 2.75″ |
| 10 W Hannover | 4 | 1.75″ |
| 1 Sw Hannover | 3 | 1.75″ |
| 7 NW Hannover | 2 | 1.00″ |
| 2 S Hannover | 1 | 3.50″ |
The season runs June through August: 21 of the 24 hail days on record fall in those 3 months (88%). July is the single busiest month, with 8 of them (33%). That peak sits inside the window rather than at either end. Hail has also been reported in September, outside that window. Reports span 4 of the 12 calendar months; the other 8 have never produced one.
| Month | Hail days |
|---|---|
| June | 7 |
| July | 8 |
| August | 6 |
| September | 3 |
That day put 7 reports on the map, the biggest 3.5 inches near Hannover. No hail day has been reported here yet this year.
| Date | Max hail | Reports |
|---|---|---|
| 2025-06-27 | 3.50″ | 7 |
| 2024-07-12 | 1.75″ | 2 |
| 2024-07-01 | 1.25″ | 1 |
| 2024-06-02 | 1.00″ | 1 |
| 2022-08-23 | 1.00″ | 1 |
| 2022-06-24 | 1.00″ | 1 |
| 2021-08-30 | 1.50″ | 1 |
| 2020-06-28 | 2.00″ | 4 |
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 3.5 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: Mercer County (33 hail days), Morton County (64) and McLean County (41). Every one of them takes more hail than Oliver County.
Mercer County · Morton County · McLean County
Back to the North Dakota hail map or the U.S. hail map.
Data & method: NOAA/NWS Storm Prediction Center reports + NOAA MRMS MESH radar, Oliver County, North Dakota only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.