NHC HURDAT2 · SPC Tornado Database
Hurricanes and Tornadoes That Hit Janesville, IA
Every tropical system within 75 miles since 1851 and every tornado within 25 miles since 1950.
Data: NOAA NHC HURDAT2 and NOAA SPC tornado and hail reports, through 2025 · Updated
1 tropical system has passed within 75 miles of Janesville, Iowa since 1851, 0 of them at hurricane strength; the most recent was an unnamed storm in 1900. Since 1950, 121 tornadoes have touched down within 25 miles, 6 of them rated EF3 or stronger.
- Hurricanes
- 0
- Tropical storms
- 1
- Tornadoes
- 121
- EF3 or stronger
- 6
within 75 mi, since 1851
below hurricane strength
within 25 mi, since 1950
11 deaths in all
What the records show for Janesville
None of the 1 tropical systems was at hurricane strength as it passed Janesville; the strongest was an unnamed storm in 1900, a tropical storm with 47 mph winds when its centre passed 75 miles away. Janesville is tied for the most tropical storms and hurricanes within 75 miles among the 241 Iowa cities on this site. The strongest of the 121 tornadoes within 25 miles was an EF5 on May 25, 2008; its path came within 4 miles, and it killed 9 people. Of the 121, 8 had paths within 5 miles of the city centre, and 60 have come since 2000. June has had the most tornadoes, 37. The most recent tornado was on August 18, 2025. Of the 241 Iowa cities, 55% have more tornadoes within 25 miles than Janesville. Hail has been reported within 10 miles 139 times since 1960, with stones up to 4.5 inches (grapefruit size). Janesville has more hail reports within 10 miles than 77% of the 241 Iowa cities.
Compare Janesville's storm record with another city →
Tropical storms and hurricanes near Janesville
| Year | Storm | Closest | Strength when closest | Peak |
|---|---|---|---|---|
| 1900 | Unnamed 1900 stormSep 11 | 75 mi | Tropical storm (47 mph) | Category 4 |
Strength is the sustained wind on the track at the closest point, which is not the wind felt in Janesville: a hurricane's worst winds sit within a few dozen miles of its centre, and inland cities are usually past that.
Tornadoes within 25 miles of Janesville
By decade
- 2020s12
- 2010s17
- 2000s31(3 EF3+)
- 1990s12
- 1980s12
- 1970s21(1 EF3+)
- 1960s16(2 EF3+)
| Date | Rating | Distance | Path | Killed / injured |
|---|---|---|---|---|
| May 25, 2008 | EF5 | 4 mi | 40.97 mi | 9 / 70 |
| Sep 1, 1961 | F4 | 16 mi | 26.6 mi | 0 / 7 |
| May 11, 2000 | F3 | 9 mi | 18.6 mi | 1 / 25 |
| Apr 16, 1960 | F3 | 18 mi | 29.8 mi | 1 / 5 |
| May 25, 2008 | EF3 | 23 mi | 31.99 mi | 0 / 3 |
| Nov 9, 1975 | F3 | 17 mi | 39.4 mi | 0 / 0 |
| Jul 14, 2021 | EF2 | 3 mi | 12.88 mi | 0 / 0 |
| Sep 6, 2001 | F2 | 5 mi | 11.5 mi | 0 / 0 |
| May 11, 2000 | F2 | 16 mi | 5 mi | 0 / 0 |
| May 11, 2000 | F2 | 13 mi | 3.6 mi | 0 / 0 |
| Jul 2, 1999 | F2 | 12 mi | 8.5 mi | 0 / 0 |
| Jun 27, 1998 | F2 | 4 mi | 25.5 mi | 0 / 0 |
The strongest 12 of 121, by rating and then by deaths. Ratings before February 2007 are on the original Fujita scale.
Hail in Janesville
The Storm Prediction Center has 139 hail reports within 10 miles of Janesville since 1960, made on 59 separate days. Of these, 101 were 1 inch across or larger, and 27 reached 2 inches. The largest, 4.5 inches (grapefruit size), fell on July 16, 2007. The most recent report is from September 22, 2025. May has the most reports, 41.
Source: NOAA Storm Prediction Center severe weather reports, data through 2025.
Weather by month in Janesville
The nearest NOAA station with 1991–2020 climate normals is Waterloo Municipal Airport, IA, 7 miles southeast of Janesville at 868 feet. July is the warmest, with an average high of 85°F and low of 64°F; January is the coolest, at 28°F and 11°F. June is the wettest at 5.7 inches of precipitation on average and January and February the driest at 1.1 inches; the year adds up to 36.2 inches over 65 days with at least a tenth of an inch. Highs reach 90°F on about 15 days a year, almost all from June to September. Lows fall below freezing on about 150 nights a year. Snowfall averages 39.1 inches a year, most of it in January. That 36.2 inches is more than at 47 of the 124 Iowa stations used on this site (38%). Waverly, 7 miles north, has its own station (Tripoli, IA): 38.7 inches a year, 2.5 more than here, and a July average high of 83°F against 85°F.
| Month | High °F | Low °F | Precip. in | Days ≥ 0.1" | Snow in |
|---|---|---|---|---|---|
| Jan | 28 | 11 | 1.1 | 3 | 10.1 |
| Feb | 33 | 15 | 1.1 | 4 | 9.3 |
| Mar | 47 | 27 | 2.0 | 5 | 4.6 |
| Apr | 61 | 38 | 4.0 | 7 | 1.7 |
| May | 73 | 50 | 4.6 | 8 | 0.1 |
| Jun | 82 | 61 | 5.7 | 8 | 0.0 |
| Jul | 85 | 64 | 4.3 | 6 | 0.0 |
| Aug | 83 | 61 | 4.2 | 6 | 0.0 |
| Sep | 77 | 52 | 3.1 | 6 | 0.0 |
| Oct | 63 | 40 | 2.8 | 5 | 0.3 |
| Nov | 47 | 28 | 1.9 | 4 | 3.1 |
| Dec | 34 | 17 | 1.4 | 4 | 9.9 |
| Year | 59 | 39 | 36.2 | 65 | 39.1 |
Averages for 1991–2020 at Waterloo Municipal Airport, IA (868 ft), from NOAA NCEI U.S. Climate Normals. Normals describe the station; the farther a place is from it, and the bigger the difference in height, the more its weather can differ.
Floods, thunderstorm wind and lightning near Janesville
Since 1996, the National Weather Service has logged 348 flood, rain, thunderstorm wind and lightning events that began within 10 miles of Janesville: 139 floods, 132 thunderstorm wind reports, 50 heavy rain events, 18 flash floods and 9 lightning strikes. They killed 0 people and injured 9, and the NWS estimated $45.2 million in property and crop damage. The strongest thunderstorm gust on record here was 105 mph, on July 10, 2009. Of the 240 Iowa cities on this site with a flash flood on record, 161 have had fewer than Janesville.
July 20, 2019: thunderstorm wind 5 miles from the centre of Janesville — 9 injured, $20,000 damage.
June 12, 2010: flood 3 miles from the centre of Janesville — $20.0 million damage.
June 7, 2008: flood 7 miles from the centre of Janesville — $2.3 million damage.
Source: NOAA NCEI Storm Events Database, events whose starting point is on record, 1996 to June 30, 2026. Damage is the NWS estimate in the dollars of the year, not insured losses, and NWS notes that some reports are unverified.
Flood insurance claims, disaster declarations and FEMA risk ratings
Flood insurance policyholders in Janesville's ZIP code 50647 have filed 42 claims with the National Flood Insurance Program since 1990, and were paid $1.0 million for buildings and contents, in the dollars of each year. The most came from Storm in 2008: 12 claims (29% of all) and $496,000. 36% of the claims carry the name of a storm or flood event; the rest have no event name. Of the 91 Iowa cities on this site with 10 or more claims, 47 have fewer than Janesville.
| Event | Claims | Paid |
|---|---|---|
| Storm2008 | 12 | $496,000 |
Bremer County, which includes Janesville, has been named in 17 federal disaster or emergency declarations since 1965, 15 of them major disasters (by incident: 8 floods, 6 severe storms, 2 biological emergencies, 1 hurricane). The latest major disaster declaration was Covid-19 Pandemic, on March 23, 2020. FEMA's National Risk Index gives Bremer County a Very Low rating for natural hazard risk overall; by hazard: Relatively Low for tornadoes, hail and strong wind; Very Low for hurricanes, inland flooding, lightning and heat waves. It models the county's expected loss from all 18 hazards it covers at $15.3 million a year, the 34th highest of 99 Iowa counties; of the hazards above, the largest share, $7.1 million (46%), is from inland flooding.
Claims: FEMA, OpenFEMA Dataset FIMA NFIP Redacted Claims – v3, summed over ZIP codes; payments in the dollars of each year, not adjusted for inflation. Declarations: Disaster Declarations Summaries – v2, by county. Retrieved October 25, 2026. This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Risk ratings: FEMA, National Risk Index county table, December 2025 (v1.20), retrieved October 26, 2026; ratings compare counties nationwide, are meant for planning and are no substitute for a local risk assessment. This product uses the Federal Emergency Management Agency's National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
What counts as a pass, the distances and the sources: how this storm history is built.