De Kalb County, Illinois Hail Map & History
De Kalb County was hit as recently as 2026-08-21, 24 days ago. De Kalb County is hit in most years. The largest stone on record here is 2.75 inches, a baseball and 2.8 times the National Weather Service's 1 inch severe criterion, reported on 2023-04-04 near Sandwich.
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 2026-08-21, around Sycamore. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls De Kalb 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 ->How often it hails in De Kalb County
NOAA's Storm Prediction Center has logged 21 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. 6 of those 17 years produced none at all. One year dominates the record: 2026 alone produced 5 of the 21 days. The last five years have run hotter than the long-run rate: 11 days since 2022, against 0.8 a year before that.
2 of the 21 days reached 2 inches or more -- 10%, or about one hail day in 10, the last on 2024-02-27. Those big days do not follow the county's usual calendar: most of them fall in February, not August. 8 of the 21 days reached golf-ball size, 1.75 inches or bigger.
Across the whole of Illinois, see the Illinois hail map and history.
Hardest-hit places in De Kalb County
Reports cluster nearest Waterman -- 4 of the county's 21 hail days -- then Sycamore (4), Sandwich (3), De Kalb (3) and Somonauk (3). Beyond those, NOAA names Shabbona, Malta and Genoa on more than one hail day apiece.
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Sandwich | 2 | 2.75″ |
| De Kalb | 2 | 1.75″ |
| Waterman | 2 | 1.75″ |
| 2 Sse Genoa | 2 | 1.00″ |
| 2 W Waterman | 1 | 2.00″ |
When it hails in De Kalb County
The season runs March through August: 20 of the 21 hail days on record fall in those 6 months (95%). August is the single busiest month, with 5 of them (24%). That peak closes the window: the season builds all the way to its worst month and then stops. Hail has also been reported in February, outside that window. Reports span 7 of the 12 calendar months; the other 5 have never produced one.
| Month | Hail days |
|---|---|
| February | 1 |
| March | 4 |
| April | 3 |
| May | 4 |
| June | 2 |
| July | 2 |
| August | 5 |
Recent De Kalb County hail days
That day put 1 report on the map, the biggest 1 inch near Sycamore. 5 hail days have already been reported this year.
| Date | Max hail | Reports |
|---|---|---|
| 2026-08-21 | 1.00″ | 1 |
| 2026-06-24 | 1.00″ | 1 |
| 2026-04-14 | 1.25″ | 5 |
| 2026-03-31 | 1.00″ | 1 |
| 2026-03-10 | 1.00″ | 1 |
| 2024-03-04 | 1.00″ | 1 |
| 2024-02-27 | 2.00″ | 3 |
| 2023-07-28 | 1.00″ | 2 |
How to read the De Kalb County map
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 2.75 inches, which is the purple band. Look up a street address with the hail history by address tool.
Nearby counties
The nearest counties with a page of their own: Kane County (44 hail days), Kendall County (17) and Lee County (18). De Kalb County sits in between.
Kane County · Kendall County · Lee County
Back to the Illinois hail map or the U.S. hail map.
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Data & method: NOAA/NWS Storm Prediction Center reports + NOAA MRMS MESH radar, De Kalb County, Illinois only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.