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 142 hail storms within 25 miles of Janesville, WI. Of those, 120 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 egg-sized, which can fracture shingle mat and dent metal flashing on contact. 2026 was the most active year on record locally, with 47 documented hail events.
Check Hail History for a Specific Address in Janesville| Severity | Count | What it means for roofs |
|---|---|---|
| Destructive | 22 events | Egg-size, expect mat fractures and gutter damage |
| Severe | 31 events | Ping pong-size, granule loss and bruising common |
| Significant | 67 events | Quarter-size, the standard insurance damage threshold |
| Moderate | 22 events | Marble-size, possible cosmetic damage |
| Year | Reported Hail Events Within 25 mi |
|---|---|
| 2026 | 47 events |
| 2025 | 44 events |
| 2024 | 15 events |
| 2023 | 18 events |
| 2022 | 18 events |
2026 was the busiest hail year on record locally for Janesville, with 47 documented events inside the 25-mile radius. Storm activity in Janesville 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 |
|---|---|---|---|---|
| 2026-08-21 | 2 N Machesney Park, IL | Moderate | 0.75" | Report from mPING: Dime (0.75 in.). |
| 2026-08-21 | 1 N Machesney Park, IL | Significant | 1.00" | Photo shared to email service account showing hailstones ranging in size between dime to quarter -- 0.5 to 1.0 inch -- in diameter. Time estimated by radar. |
| 2026-08-07 | 3 NE Janesville, WI | Moderate | 0.75" | Broadcast MET reports estimated dime to penny size hail NE of Janesville, with estimated 40-50 MPH wind gusts. |
| 2026-06-24 | 2 SE Milton, WI | Significant | 1.25" | — |
| 2026-06-24 | MILTON, WI | Significant | 1.25" | — |
| 2026-04-17 | ROCKTON, IL | Significant | 1.00" | — |
| 2026-04-17 | 4 NE Durand, IL | Severe | 1.75" | Relayed via mping. Time estimated by radar. |
| 2026-04-17 | 2 NE Lake Summerset, IL | Destructive | 2.25" | Time estimated by radar. Relayed via mping. |
| 2026-04-17 | South Beloit, IL | Severe | 1.50" | Relayed via mping. Time estimated by radar. |
| 2026-04-17 | South Beloit, IL | Significant | 1.25" | Report from mPING: Half Dollar (1.25 in.). |
| 2026-04-17 | 1 S Durand, IL | Severe | 1.75" | Hail of at least golf ball size ongoing on south side of Durand. |
| 2026-04-17 | South Beloit, IL | Moderate | 0.50" | Report from mPING: Half-inch (0.50 in.). |
| 2026-04-17 | DURAND, IL | Severe | 1.75" | — |
| 2026-04-17 | 1 SE Durand, IL | Destructive | 2.25" | Hen egg size hail south of Durand. Relayed via mping. |
| 2026-04-17 | LAKE SUMMERSET, IL | Destructive | 2.25" | — |
| 2026-04-17 | South Beloit, IL | Severe | 1.50" | Report from mPING: Ping Pong Ball (1.50 in.). |
| 2026-04-17 | 3 W Rockton, IL | Significant | 1.00" | Relayed via mping. |
| 2026-04-17 | SOUTH BELOIT, IL | Severe | 1.50" | — |
| 2026-04-17 | 3 E South Beloit, IL | Moderate | 0.75" | Report from mPING: Dime (0.75 in.). |
| 2026-04-17 | BELOIT, WI | Severe | 1.75" | — |
NOAA has recorded 137 high-wind events within 25 miles of Janesville, WI in the past five years. Of those, 137 reached severe-thunderstorm thresholds (58+ mph). The highest measured gust was 100 mph.
| Severity | Count |
|---|---|
| Destructive | 1 event |
| Severe | 42 events |
| Significant | 94 events |
| Date | Location | Gust (mph) | Severity | NOAA Comments |
|---|---|---|---|---|
| 2026-08-09 | 4 NE Edgerton, WI | 59 | Significant | 59 mph wind gust recorded via weather station mounted to roof. |
| 2026-07-03 | 1 S Darien, WI | 63 | Significant | Private Weather Station. |
| 2026-07-03 | 2 SE Darien, WI | 100 | Destructive | *** 3 FATAL, 2 INJ *** NWS Storm Survey for Walworth County: Damage from south of Darien through Lake Delavan to Como occurred due to downburst winds and not a tornado. Estimated peak winds of 90-100mph from about 5-10 barns that were destroyed/heavily damaged and hundreds of trees that were snapped at the trunk or uprooted. Witnesses in the area described it as a three round burst of high winds. 2 injuries documented SW of Delavan Lake when 3 20 foot by 90 foot empty silos collapsed and fell on motorcyclists that were seeking shelter from a storm. 3 people drowned in a capsized boat on Geneva Lake from the winds associated with this storm. |
| 2026-06-28 | 3 N Poplar Grove, IL | 51 | Significant | Personal weather station measured a wind gust of 51 mph. |
| 2026-06-24 | MILTON, WI | 60 | Significant | There was a report of three large tree limbs down from a healthy tree in Milton. |
| 2026-06-24 | Milton, WI | 60 | Significant | About 3 large limbs out of a healthy tree in Milton. |
| 2026-06-11 | FONTANA, WI | 58 | Significant | Local official reports a large downed tree branch on Hill Street in the community of Walworth. Wind gust estimated from radar data. |
| 2026-06-10 | LAKE SUMMERSET, IL | 60 | Significant | Large tree limbs were downed over powerlines. Picture sent via social media. Time estimated by radar. |
| 2026-06-10 | EDGERTON, WI | 60 | Significant | Public report of a large downed tree branch in Edgerton. Wind gust estimated from radar data and damage. |
| 2026-06-10 | 6 N Shirland, WI | 85 | Severe | 85 MPH wind gust estimated from home instrumentation. |
| 2026-06-10 | FULTON, WI | 81 | Severe | Trained spotter estimates 80 MPH wind gusts just west of Edgerton. |
| 2026-06-10 | 4 W Edgerton, WI | 80 | Severe | Trained spotter estimates 80 MPH wind gusts. |
| 2026-06-10 | NEWARK, WI | 85 | Severe | Trained spotter estimates 85 MPH wind gusts from observations and home weather station. |
| 2026-06-10 | CHARLIE BLUFF, WI | 81 | Severe | Trained spotter estimates 80 MPH wind gusts near Milton. |
| 2026-06-10 | BUSSEYVILLE, WI | 85 | Severe | Trained spotter estimates 85 MPH wind gusts to the southeast of Rockdale. |
| 2026-06-10 | 1 E Fort Atkinson, WI | 75 | Severe | Trained spotter estimates 75 MPH wind gusts. |
| 2026-06-10 | 2 NW Milton, WI | 80 | Severe | Trained spotter estimates 80 MPH wind gusts. |
| 2026-06-10 | 6 SE Rockdale, WI | 85 | Severe | Trained spotter estimates 85 MPH wind gusts. |
| 2026-06-10 | MILTON, WI | 60 | Significant | Public report of a large downed tree branch. Wind gust estimated from radar data and damage. |
| 2026-06-10 | FT ATKINSON, WI | 75 | Severe | Trained spotter estimates 75 MPH wind gusts in Fort Atkinson. |
The most recent quarter-size-or-larger hail storm recorded by NOAA within 25 miles of Janesville was on August 21, 2026. HailCheck refreshes from the NOAA Storm Events database daily, so newer events appear here as they are reported.
Janesville averages roughly 28 reported hail events per year within a 25-mile radius. Significant storms (quarter-size or larger) account for 120 of the 142 events recorded over the last five years.
The largest documented hail near Janesville in the last five years was egg-sized. Most Janesville-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 WI 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 Janesville. 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 Janesville 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 ValidationJanesville 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.