Winnebago County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Winnebago County: 1.
2. Weak tornadoes were under-recorded before Doppler radar coverage became national in the early 1990s, so earlier decades read low. Ratings use the Fujita scale before February 2007 and the Enhanced Fujita scale after.

Storm Prediction Center severe weather database, 1950 to 2025.

Smoke overhead

1. A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.

NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.

Claims by ZIP code

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).

OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.

River crests

River gauges

1. Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.

NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.

1. The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.

NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.

More event types since 1996

Costliest events since 1996

1. Jul 27, 2026Tornado$88.0 million
   National Weather Service narrative

   An NWS Damage Survey team confirmed a tornado that originated in Outagamie County around 11:56 AM CDT continued moving south, entering northeastern Winnebago County around 12:00 PM CDT. The tornado produced EF1 damage by snapping and uprooting trees and damaging residential buildings just south of the Fox River. The tornado continued to widen and eventually strengthened again to EF2 damage just south of Palisades Drive by uplifting significant portions of the roof deck and collapsing garage doors to residences with winds of 120 mph. The tornado continued to strengthen and widen, reaching a width of 1400 yards and producing EF3 damage to a well-built low-rise brick building just…

2. Jun 12, 2008Flash Flood$18.6 million
   National Weather Service narrative

   Heavy rainfall, totaling 5.41 inches for the day, over already saturated ground caused widespread flash flooding in the Oshkosh area. Sewage backed up into many basements and the foundations of some homes on the south side of the city crumbled, making them uninhabitable. The flooding destroyed 20 homes, caused major damage to 150, and caused minor damage to over 400 others. Several schools sustained damage, including Lourdes High School and the attached St. John Neumann Middle School, which had extensive water and sewage damage. Water built up in the parking lot and caved in windows on the school's lower level. Flood waters rose over five feet, destroying classrooms, athletic…

3. May 12, 2000Hail$10.4 million
   National Weather Service narrative

   During the mid and late morning of May 12, a high precipitation supercell thunderstorm developed in west-central Wisconsin and tracked east across the state for over two and a half hours. The storm produced a prolific path of large hail, a brief tornado, and a significant wet microburst across central and east central Wisconsin. The storm was one of the most damaging thunderstorms in Wisconsin history, producing well over $100 million in damage.The thunderstorm developed north of a warm front, which was located across the Wisconsin/Illinois border. The setup was favorable for what is known as "elevated" convection; that is, the source of the instability was aloft, and not…

4. Jul 20, 2010Hail$9.0 million
   National Weather Service narrative

   Hail, up to golf ball size, damaged hundreds of vehicles and more than 200 homes in northeast Winnebago County. The wind-driven hail caused significant damage to roofs and siding.

5. Apr 10, 2011Thunderstorm Wind$5.0 million
   National Weather Service narrative

   Thunderstorm downburst wind gusts, estimated in the 75 to 100 mph range, caused major damage to 2 large industrial buildings in the Neenah-Menasha area. Much of the west-facing wall of one building was blow inward. The high winds also downed trees and power lines, knocked down an 80-foot ham radio tower, bent a large flagpole, downed fences and threw a carport into a yard two houses down the street.

6. Jun 11, 2001Thunderstorm Wind$4.5 million
   National Weather Service narrative

   During the late evening of June 11th a large thunderstorm complex, including a bow echo, moved across central and east central Wisconsin. Winds exceeded 70 mph across the area, resulting in thousands of downed trees and damage to homes and businesses. What made the storm particularly significant was the sustained strong winds causing more damage than typically experienced with a single severe wind gust. In Oshkosh, winds of 45 to 70+ mph were recorded for 45 minutes, veering from west to north during that span. The high winds and rough water knocked over dozens of sailboats on Lake Winnebago, sinking at least one. The storms knocked out power to at least 100,000 customers. The…

7. Apr 10, 2011Tornado$1.4 million
   National Weather Service narrative

   The tornado that formed near Poy Sippi crossed into Winnebago County at 8:04 pm CDT (1904 CST). The tornado moved along the north shore of Lake Poygan, causing most of its damage near Boom Bay on the northeast shore. Two homes were heavily damaged as portions of their roofs were partially ripped off (DI 2, DOD 4). Several other houses sustained lesser damage in this area. In addition, two small mobile homes were rolled on their side (DI 3, DOD 5) and many trees were uprooted or snapped. The tornado dissipated about 2 miles west of Winchester, although damage occurred east and southeast of this location from straight-line thunderstorm winds. The average path width was 100 yards.

8. Jun 11, 2004Flood, Winnebago$876,000
   National Weather Service narrative

   Three to four inches of rain fell over Waushara county and the southern half of Winnebago county during the morning hours of the 11th. Many rivers in that part of the state were already swollen after weeks of much above normal rainfall. The torrential rainfall flooded streets and highways, including U.S. Highway 41 (the major highway through Winnebago co.). A bridge on the west side of Oshkosh (Winnebago co.) sustained damage, from the high waters of Sawyer Creek, and had to be closed until it could be inspected. Highways reopened to traffic by the afternoon of the 12th. Flooding of streets and numerous homes and businesses caused the closure of downtown Wautoma (Waushara co.).…

9. May 3, 2012Lightning$750,000
   National Weather Service narrative

   Lightning stuck an electrical box, starting a barn fire that destroyed the barn and a recreational vehicle, and killed 13 show horses.

10. Jun 8, 2008Flood$625,000
    National Weather Service narrative

    Thunderstorms with rainfall rates of 1 to in excess of 2 inches per hour moved across Oshkosh early during the evening. The combination of heavy rain and ground that was saturated from rain that fell earlier in the day resulted in damage to about 100 homes and 5 businesses in Oshkosh. Most of the damage was due to basement flooding and ponding of water around building foundations. Many streets in the city were impassible due to nearly a foot of standing water. By the end of the day Oshkosh had a total of 4.13 inches of rain.

1. Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.

NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.

All-time high

107°FJul 13, 1936

All-time low

−34°FFeb 20, 1929

Warmest night

86°F2 times, most recently Jul 10, 1936

Coldest day

−19°FJan 19, 1994

Wettest day

5.40 inAug 4, 1924

Snowiest day

13.0 inMar 16, 2026

Hottest year

2024mean 50.7°F

Coldest year

1917mean 42.3°F

Wettest year

201944.01 in

Driest year

189918.88 in

Snowiest season

87.2 in1978-79

Station Oshkosh (USC00476330), 750 ft elevation, 5.7 miles from the population centre. Daily records from 1893 to October 23, 2026; 99.2% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.

NOAA NCEI Global Historical Climatology Network Daily.

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).

OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.

Neighbouring counties

• Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
• Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
• Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
• Storm events NOAA NCEI Storm Events Database, through 2026.
• Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
• Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
• Weather records NOAA NCEI Global Historical Climatology Network Daily, station USC00476330.
• River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
• Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
• Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
• Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.

Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.