The most recent reported hail day was 2026-04-15, 107 days ago. Boone County is hit in most years. The largest stone on record here is 2 inches, a hen egg and twice the National Weather Service's 1 inch severe criterion, reported on 2014-04-12 near Poplar Grove.
Colored swath = NOAA MRMS radar-estimated hail size; dots = NOAA SPC reports in Illinois. Radar-indicated, not a guarantee of damage.
The last hail here fell on 2026-04-15, around Poplar Grove. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls Boone County addresses inside a hail swath above your size threshold into a door-knock list you can export, scoped to your approved markets.
Get free access Check an addressOur US-based call center calls the homeowners in this storm and books roof inspections straight onto your calendar. You work the storm; we fill the schedule. We dial -- you do not have to knock a single door.
See call-center options ->NOAA's Storm Prediction Center has logged 20 separate hail days here since 2010 -- 1.2 a year over 17 years of record. Those days carry 43 separate reports between them, two or three on a typical one. 5 of those 17 years produced none at all. The busiest single year was 2017, with 3 hail days. The last five years track the long-run rate, with 6 days since 2022.
Most hail here stays under 2 inches: only 1 of the 20 days on record passed it, 5%, the last on 2014-04-12. Those big days do not follow the county's usual calendar: most of them fall in April, not May. 5 of the 20 days reached golf-ball size, 1.75 inches or bigger.
Across the whole of Illinois, see the Illinois hail map and history.
Reports cluster nearest Belvidere -- 14 of the county's 20 hail days -- then Poplar Grove (7) and Timberlane (3). That one town is named on 70% of them.
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Belvidere | 8 | 1.75″ |
| Poplar Grove | 6 | 2.00″ |
| 1 NNW Belvidere | 3 | 1.00″ |
| 1 WNW Belvidere | 2 | 1.75″ |
| 1 NNE Belvidere | 2 | 1.25″ |
The season runs April through July: 16 of the 20 hail days on record fall in those 4 months (80%). May is the single busiest month, with 6 of them (30%). That peak sits inside the window rather than at either end. Hail has also been reported in March, August and September, outside that window. Reports span 7 of the 12 calendar months; the other 5 have never produced one.
| Month | Hail days |
|---|---|
| March | 1 |
| April | 5 |
| May | 6 |
| June | 3 |
| July | 2 |
| August | 2 |
| September | 1 |
That day put 1 report on the map, the biggest 1 inch near Poplar Grove. 2 hail days have already been reported this year.
| Date | Max hail | Reports |
|---|---|---|
| 2026-04-15 | 1.00″ | 1 |
| 2026-04-14 | 1.75″ | 6 |
| 2025-08-16 | 1.00″ | 2 |
| 2025-05-15 | 1.00″ | 2 |
| 2023-06-28 | 1.00″ | 3 |
| 2022-04-30 | 1.50″ | 2 |
| 2021-09-07 | 1.75″ | 1 |
| 2020-08-10 | 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 2 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: Winnebago County (41 hail days), McHenry County (35) and Ogle County (25). Every one of them takes more hail than Boone County.
Winnebago County · McHenry County · Ogle County
Back to the Illinois hail map or the U.S. hail map.
Data & method: NOAA/NWS Storm Prediction Center reports + NOAA MRMS MESH radar, Boone County, Illinois only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.