Waukesha County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Waukesha 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.

1. Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the county boundary (or inside the county).
2. Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).

USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.

Mapped landslides

Mapped by NASA (1).

1. Landslides mapped in the USGS compilation of landslide inventories across the United States (version 3.0, 2025), rated probable or better. The compilation joins inventories made by federal and state agencies for different purposes and areas, so the number mapped in a county reflects how closely it has been surveyed as much as how often its slopes fail. An area with few records may simply not have been mapped. Deaths are as recorded in the inventories; a slide listed in two inventories is counted once.

USGS Landslide Inventories across the United States, version 3.0, retrieved October 27, 2026.

More event types since 1996

Costliest events since 1996

1. Aug 9, 2025Flash Flood$89.0 million
   National Weather Service narrative

   Widespread flash flooding of streets, creeks, rivers, and low lying neighborhoods and homes occurred especially in New Berlin, Brookfield, Butler, Menomonee Falls, Elm Grove, and Muskego. Some of the more notable creeks or rivers that flooded were the Fox and Menomonee Rivers and their tributaries. The Butler Ditch, Jewel Creek, Root River, and other unnamed creeks also flash flooded. For all of Waukesha County, 3 homes were classified as destroyed, 310 homes and businesses sustained major damage, 221 with minor damage and 119 with affected damage. These damages were from a variety of 1st floor flooding, basement flooding, and foundation collapse. Residential sewage backups, and…

2. Jun 8, 2008Flash Flood$63.0 million
   National Weather Service narrative

   Heavy rains resulted in flash flooding across much of Waukesha County. Water reached depths of 3 feet or more and several cars stalled. This was one of 4 flash floods in Waukesha County that occurred on Junen 7th and 8th. Collectively, each of these 4 flash floods resulted in home and business damage along with some crop losses. It was nearly impossible to break down the damages by flash flood event. Therefore, the collective breakdown for all of Waukesha County is provided in this flash flood event.||The breakdown for residential home losses were: 1433 with minor damage, 188 with major damage, and 1 destroyed (total of $54.632 million for home losses). Business losses totaled…

3. Jun 21, 2010Tornado$20.6 million
   National Weather Service narrative

   An EF2 tornado developed about 1.9 miles west-southwest of the Village of Eagle, roughly 1/2 mile south-southeast of the intersection of STH 59 and CTH S, just west of CTH S and west of a horse-riding ranch, and moved east-northeast through the Eagle and then moved due east and then east-southeast before dissipating about 1.94 miles southeast of Jericho, just within Mukwonago County Park, 1000 feet east of Genevieve Drive. Fifteen people sustained minor injuries. One hundred thirty-four homes received minor damage, 67 homes had major damage, and 8 homes were destroyed, mainly in the southern part of the village. Another 75 homes were minimally affected. One business received major…

4. Aug 6, 1998Flash Flood$17.3 million
   National Weather Service narrative

   A monumental flash flood event ravaged adjacent portions of Milwaukee and Waukesha counties during the afternoon and evening hours. For the northwest quarter of Milwaukee Co., and the northeast/ eastcentral parts of Waukesha Co., it was the second year in row (press headline - "deja vu all over again"). In Milwaukee Co., the damage wasn't as bad as that in June 1997, but for Waukesha Co. it was the worst flooding ever. Here are the details broken down by county: 1) Milwaukee County...The flash flood was the result of 5 to almost 9 inches of rain, between 1330CST (230pm) and 2000CST (9pm), falling on top of 1 to 3 inches that fell the previous two days. Maximum storm rainfall was…

5. Aug 9, 2025Flash Flood$9.0 million
   National Weather Service narrative

   Widespread flash flooding of streets, creeks, rivers, and low lying neighborhoods and homes occurred especially in New Berlin, Brookfield, Menomonee Falls, Waukesha, Pewaukee, Merton, and Muskego. Some of the more notable creeks or rivers that flooded were the Fox River, Jewel Creek, and their tributaries, as well as some lake flooding. Some flood damage occurred to homes especially near Linnie Lac Lake toward Little Muskego Lake. These damages were from a variety of 1st floor flooding, basement flooding, and foundation collapse. Residential sewage backups, and raw sewage released into rivers by many municipalities were common. A small number of complete road washouts and swift…

6. Apr 14, 2026Tornado$7.4 million
   National Weather Service narrative

   Tornado appeared to develop in the Lisbon Oaks subdivision, causing mainly tree damage before intensifying closer to Highway 164. The tornado was at it's most intense near Indian Grass Lane where it caused damage to multiple businesses. The strongest damage was to an insurance car shop port that had a well anchored roof that was completely blown off and found approximated 3 to 4 blocks to the east near Highway 164. Damage then occurred to a church near Wildwood Way and multiple homes along Conservancy Court. Tornado appeared to end near Waukesha Ave along Linda Dr.

7. May 31, 1998Thunderstorm Wind$6.7 million
   National Weather Service narrative

   During the early morning hours of Sunday, May 31st, southcentral and southeast Wisconsin experienced an unprecedented, widespread downburst wind event known as a "derecho." Incredibly powerful, hurricane-force straight-line winds, with peak gusts of 100 to 128 mph tore through 12 counties in this part of the state, while another 8 counties had peak gusts of 60 to 80 mph. Residents noted that the strongest winds only lasted a minute or two, but gusty winds hung on for 15 to 30 minutes. Meteorologically, a solid squall line developed in southern Minnesota and gathered strength as it raced east with a translational speed of 50 to 60 mph across southcentral and southeast Wisconsin.…

8. Jun 21, 1997Flash Flood$5.4 million
   National Weather Service narrative

   Flash flooding occurred primarily in eastern Waukesha county as a result of heavy rainfall amounts in excess of 5 to over 8 inches in a 30 hour period ending about 1000CST. This flash flooding was greater than a "100 year rainfall" based on rainfall frequency maps. No one was injured or killed by the flood waters, thanks to superb rescue efforts by local law enforcement officials and firefighters. Besides public sector damage in county/city parks, there was private and business damages. The hardest hit area was the city of Menomonee Falls, followed by New Berlin, Lannon, Sussex, and the town of Lisbon. Spotty flash flooding was noted in the cities of Oconomowoc, Hartland,…

9. Apr 13, 2006Hail$4.4 million
   National Weather Service narrative

   Wild weather occurred over parts of south-central and southeast Wisconsin on April 13, 2005. Wisconsin's most-costly hailstorm pummeled a large swath from around Mineral Point (Iowa Co.) to north of Milwaukee (Milwaukee Co.), while hurricane-force thunderstorm winds raked parts of Fond du Lac and Sheboygan Counties. Here's what happened: scattered supercells developed in eastern Iowa during the late afternoon hours of April 13th and pushed east-northeastward through southern Wisconsin and northern Illinois during the evening. Three main hailstorms affected southern Wisconsin. The first hailstorm left a swath of hail and hail damage from southern Iowa County (around 1945CST),…

10. Apr 13, 2006Hail$4.4 million
    National Weather Service narrative

    Hail sized ranged from 1.00 to 2.00 inches in diameter.

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

103°F3 times, most recently Jul 5, 2012

All-time low

−26°F2 times, most recently Feb 3, 1996

Warmest night

84°FJul 14, 1995

Coldest day

−13°FJan 15, 1972

Wettest day

6.81 inAug 6, 1986

Snowiest day

16.7 inFeb 10, 1960

Hottest year

2024mean 52.8°F

Coldest year

1972mean 43.6°F

Wettest year

201946.01 in

Driest year

196319.10 in

Snowiest season

99.1 in2007-08

Station Milwaukee Mitchell Airport (USW00014839), 667 ft elevation, 17.7 miles from the population centre. Daily records from 1938 to October 26, 2026; 100.0% 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 USW00014839.
• 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.
• Landslides USGS Landslide Inventories across the United States, version 3.0 (2025).
• 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.