Data current as of 2026-10-16 · Sourced from NOAA Storm Events
Over the past five years, the National Oceanic and Atmospheric Administration has recorded 217 hail storms within 25 miles of O'Fallon, IL. Of those, 213 produced hail at least quarter-size — the threshold most insurance carriers consider potentially damaging to asphalt shingles. The largest reported hail in this window was baseball-sized or larger, which can fracture shingle mat and dent metal flashing on contact. 2025 was the most active year on record locally, with 91 documented hail events.
Check Hail History for a Specific Address in O'Fallon| Severity | Count | What it means for roofs |
|---|---|---|
| Catastrophic | 1 event | Baseball+ size, structural roof damage likely |
| Destructive | 15 events | Egg-size, expect mat fractures and gutter damage |
| Severe | 62 events | Ping pong-size, granule loss and bruising common |
| Significant | 135 events | Quarter-size, the standard insurance damage threshold |
| Moderate | 3 events | Marble-size, possible cosmetic damage |
| Minor | 1 event | Pea-size, unlikely to damage modern shingles |
| Year | Reported Hail Events Within 25 mi |
|---|---|
| 2026 | 82 events |
| 2025 | 91 events |
| 2024 | 20 events |
| 2023 | 21 events |
| 2022 | 3 events |
2025 was the busiest hail year on record locally for O'Fallon, with 91 documented events inside the 25-mile radius. Storm activity in O'Fallon typically peaks in spring and early summer, when the jet stream pushes Gulf moisture into the area and supercell thunderstorms become more frequent.
| Date | Location | Severity | Size | NOAA Comments |
|---|---|---|---|---|
| 2026-08-22 | Grantfork, IL | Severe | 1.50" | — |
| 2026-08-22 | Aviston, IL | Severe | 1.50" | — |
| 2026-08-22 | Highland, IL | Destructive | 2.50" | Picture of tennis ball size hail relayed from a viewer of WCIA. |
| 2026-08-22 | 3 SE Grantfork, IL | Severe | 1.75" | — |
| 2026-05-18 | 1 NNE Oakville, MO | Moderate | 0.70" | NWS employee reported dime-size hail. |
| 2026-05-04 | 2 NNE Bethalto, IL | Moderate | 0.75" | Lasted about 5 minutes. |
| 2026-05-04 | Bethalto, IL | Significant | 1.00" | — |
| 2026-05-04 | 1 SSE Wood River, IL | Moderate | 0.70" | — |
| 2026-05-04 | 1 NE Alton, IL | Severe | 1.75" | Report from mPING: Golf Ball (1.75 in.). |
| 2026-05-04 | 1 NNE Bethalto, IL | Severe | 1.50" | — |
| 2026-05-04 | 2 E Worden, IL | Severe | 1.75" | — |
| 2026-05-04 | WORDEN, IL | Severe | 1.50" | — |
| 2026-05-04 | 2 W Worden, IL | Severe | 1.50" | — |
| 2026-05-04 | DE CAMP, IL | Severe | 1.75" | — |
| 2026-05-03 | (ALN)STL RGNL ARPT A, IL | Significant | 1.00" | — |
| 2026-05-03 | COTTAGE HILLS, IL | Severe | 1.50" | — |
| 2026-05-03 | MILTON, IL | Severe | 1.75" | — |
| 2026-05-02 | 1 E Fairview Heights, IL | Minor | 0.25" | Mostly smaller than pea sized. |
| 2026-04-28 | 3 SE Columbia, IL | Significant | 1.00" | Report from mPING: Quarter (1.00 in.). |
| 2026-04-28 | Bethalto, IL | Significant | 1.25" | — |
NOAA has recorded 153 high-wind events within 25 miles of O'Fallon, IL in the past five years. Of those, 153 reached severe-thunderstorm thresholds (58+ mph). The highest measured gust was 100 mph.
| Severity | Count |
|---|---|
| Destructive | 2 events |
| Severe | 115 events |
| Significant | 36 events |
| Date | Location | Gust (mph) | Severity | NOAA Comments |
|---|---|---|---|---|
| 2026-06-25 | FERGUSON, MO | 58 | Significant | A thunderstorm produced strong winds which snapped a large tree. The tree fell onto a garage and damaged it. |
| 2026-04-28 | 1 S Swansea, IL | 55 | Significant | — |
| 2026-04-28 | Hamel, IL | 70 | Severe | — |
| 2026-04-27 | TOWER GROVE, MO | 58 | Significant | Thunderstorm winds downed one power line on McCausland and one small tree at IKEA. |
| 2026-04-27 | MARINE, IL | 58 | Significant | Thunderstorm winds damaged a shed near Marine. |
| 2026-04-27 | BELLEVILLE, IL | 58 | Significant | Thunderstorm winds blew a tree onto a home 2 miles southeast of Belleville. Three individuals sustained injuries. Near Swansea and at Scott Air Force Base, winds downed large tree limbs. A report of an estimated 55 mph wind gust was reported in Swansea, but winds were likely stronger based on the damage. |
| 2026-04-27 | HAMEL, IL | 70 | Severe | Thunderstorm winds downed a large portion of a tree onto a home in Hamel. A member of the public estimated 70 mph wind gusts were occurring a few minutes later. |
| 2026-03-15 | NEW ATHENS, IL | 60 | Significant | A trained spotter estimated 60 mph winds in New Athens a few minutes after a tornado with max wind gusts of 90 mph struck the town. |
| 2026-03-15 | OKAWVILLE, IL | 70 | Severe | A broadcast meteorologist reported wind gusts of 60 to 70 mph in Okawville. |
| 2026-03-15 | COLLINSVILLE, IL | 60 | Significant | A TV meteorologist noted several gusts over 60 mph in his station's Storm Runner vehicle. |
| 2026-03-11 | NEW ATHENS, IL | 58 | Significant | Thunderstorm winds downed a tree which blocked Baldwin Road near New Athens. They also downed power lines and damaged a home to an unknown degree. |
| 2026-03-11 | VENEDY, IL | 58 | Significant | Thunderstorm winds knocked a tree down onto County Highway 6 east of Venedy. |
| 2026-03-11 | (ALN)STL RGNL ARPT A, IL | 67 | Severe | A 67 mph wind gust was reported at Alton Regional Airport. |
| 2025-08-12 | MILTON, IL | 69 | Severe | Thunderstorm winds knocked down power lines and caused damage to structures near Alton. |
| 2025-07-06 | CASEYVILLE, IL | 74 | Severe | Thunderstorm winds downed multiple trees and wires in Caseyville and Collinsville. |
| 2025-07-06 | LEBANON, IL | 69 | Severe | Thunderstorm winds downed a large tree across Route 4 in Lebanon. |
| 2025-06-27 | ROCK HILL, MO | 69 | Severe | Several large tree limbs and trees were reported downed in a swath from Webster Groves/Shrewsbury southeast through Marlborough and Wilbur Park/Affton. |
| 2025-05-16 | GRAVOIS, MO | 69 | Severe | A man was driving on Grand Drive in Carondelet Park when a tree was uprooted and collapsed on his truck. He was killed instantly. This was not due to the tornado but possibly from rear flank downdraft winds on the south side of the supercell. |
| 2025-05-16 | GRANT, MO | 69 | Severe | Thunderstorm winds damaged a carport near Affton. |
| 2025-05-16 | EAST SWANSEA, IL | 69 | Severe | There were several reports of trees and power lines down over northern St. Clair County. |
The most recent quarter-size-or-larger hail storm recorded by NOAA within 25 miles of O'Fallon was on August 22, 2026. HailCheck refreshes from the NOAA Storm Events database daily, so newer events appear here as they are reported.
O'Fallon averages roughly 43 reported hail events per year within a 25-mile radius. Significant storms (quarter-size or larger) account for 213 of the 217 events recorded over the last five years.
The largest documented hail near O'Fallon in the last five years was baseball-sized or larger. Most O'Fallon-area hail falls in the marble-to-quarter range, with destructive storms (egg-size or larger) appearing roughly once every few years.
Most homeowners insurance policies in IL cover hail damage to roofs, siding, and gutters under the dwelling and other-structures coverage. Coverage typically requires the damage to be tied to a verifiable storm date — which is where the NOAA hail history above (and a HAAG-style test square validation) becomes important for the claim file.
Use the HailCheck address search to enter any street address in or near O'Fallon. HailCheck returns every NOAA hail event within a configurable radius, along with severity bands, dates, and storm narratives for Pro members.
If your property in or near O'Fallon took on hail during one of the storms above, the standard process for documenting damage is a 10×10 foot test square inspection. A HAAG-trained reviewer counts impact indicators — granule displacement, mat fractures, and bruising — within the marked square and produces a PASS or FAIL document for the claim file.
HailCheck offers a $99 photo-based HAAG-style test square validation. You submit photos from the field, our reviewer evaluates the impact indicators and cross-references the NOAA storm dates listed above, and a written PASS/FAIL determination is returned within one business day. We do not send anyone to the roof — the validation is built around the photos you submit.
Learn About $99 HAAG-Style ValidationO'Fallon sits east of the traditional hail alley, where hail events are less frequent than the central plains but tend to be associated with strong squall lines and tropical systems. Local roof systems are less commonly hardened for hail, which can mean even moderate impacts produce claim-worthy damage.