Ozaukee County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Ozaukee County: 0.
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.

More event types since 1996

Costliest events since 1996

1. Apr 13, 2006Hail$6.3 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),…

2. Jun 18, 1996Flash Flood$5.3 million
   National Weather Service narrative

   Torrential rainfalls due to "training" thunderstorms moving N/NW into Port Washington resulted in probably the worst flash flooding ever experienced by that city. Within about 2 hours the city picked up 6 to over 7 inches of rain... on top of 5 to 6.5 inches that fell in the previous two days. Water reached 3 to 4 feet deep on some roads, while most manhole covers were swept away. A state of Emergency was declared by city officials at 0800CST, with the height of the storm occurring at 0830 to 0900CST. Mudslides were reported on several of the city's hills. Whole sections of some city streets were washed away. A ramaging Sauk Creek, running through the city, severely damaged the…

3. Jun 18, 1996Flood, Ozaukee$3.9 million
   National Weather Service narrative

   A series of thunderstorms "trained" N/NW into Ozaukee county and dumped heavy rains from 2 inches to over 7 inches on June 18th. Total rainfalls for the 3-day period of the 16th, 17th, and 18th ranged from 5 to over 13 inches (see Port Washington flash flood report for 06/18/96). There were many reports of flooding of basements, businesses, farm land, and low lands along rivers, streams, and creeks. Some roads were blocked for extended periods of time in Mequon, Cedarburg, Saukville, and Thiensville. Trash dumpsters were carried away by water 3 feet deep in Thiensville. Farm land sustained soil erosion and crop damage. The Milwaukee River on the east side of Cedarburg crested at…

4. Jun 21, 1997Flash Flood$3.6 million
   National Weather Service narrative

   Flash flooding occurred in southern Ozaukee county as a result of heavy rainfall amounts in excess of 8 inches over a 30 hour period ending about 1200CST. 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 widespread private and business damages. The hardest hit areas were the cities of Mequon and Thiensville, a small area about 2 miles southwest of Fredonia, and east of Cedarburg. By mid-morning much of downtown Thiensville was issentially a…

5. May 31, 1998Thunderstorm Wind$3.5 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.…

6. Jun 1, 2004Flood, Ozaukee$2.6 million
   National Weather Service narrative

   Scattered to widespread heavy rains across south-central and southeast Wisconsin during the period of June 9-12, 2004 kept many rivers and streams at or above flood stage for a good part, or most of the month. Monthly rainfall totals generally ranged from 4 to 7 inches across south-central and southeast Wisconsin, with some scattered spots in Sauk, Columbia, Dodge, Walworth, Racine, and Kenosha Counties picking up 7 to 9.5 inches, or 50 to 100% above normal. In some cases, stretches of some rivers actually went above flood stage in May, 2004. Refer to flood and flash flood events in May, 2004, for additional information. During June, 2004, the high water levels kept much of the…

7. Jun 23, 2010Lightning$1.0 million
   National Weather Service narrative

   A lightning strike in the city of Mequon resulted in a fire at a strip mall in the 1100 block of North Port Washington Road that destroyed 9 businesses. Time is estimated. Other severe weather was reported in southern Wisconsin during the pre-dawn hours of June 23, 2010.

8. Jun 18, 1996Flash Flood$1.0 million
   National Weather Service narrative

   Heavy rainfalls of 5 to 6 inches (unofficial) within a 2 to 3 hour time period resulted in flash flooding in Belgium. There was the usual basement and business flooding. Portions of 2 roads and 2 bridges in the countryside around Belgium were washed out.One of the roads was Forest Beach Lane near the Lake Michigan shoreline.

9. Aug 27, 2018Flood$854,000
   National Weather Service narrative

   Overall, many flooded roads and lowlands due to 4 to 8 inches of rain. Some road washouts and homes flooded. I-43 was closed through late morning due to flooding between mile marker 101 and 107. Many of the cities in the county experienced severe street flooding and closures. The Milwaukee River reached minor flood stage throughout the county with many roads and intersections flooded and closed near the river, especially near Saukville and Cedarburg. Some piers washed away on the Milwaukee River. Dozens of vehicles across the county were stranded in flood waters. Overall, 76 homes sustained affected flood damage, 52 homes with minor flood damage, and 11 homes with major damage. 25…

10. Jul 4, 2005Lightning$500,000
    National Weather Service narrative

    A severe thunderstorm pushed across Ozaukee County during the morning of Independence Day. It produced penny sized hail in Cedarburg. Earlier storms had lightning which struck a condominium complex in Mequon. The resultant fire had 20-foot flames as the building burnt to the ground.

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

104°FJul 6, 2012

All-time low

−40°F2 times, most recently Jan 11, 1982

Warmest night

81°FJul 14, 1995

Coldest day

−18°FJan 19, 1994

Wettest day

8.62 inAug 10, 2025

Snowiest day

15.3 inFeb 7, 2008

Hottest year

2012mean 49.7°F

Coldest year

2014mean 42.5°F

Wettest year

202543.68 in

Driest year

196218.81 in

Snowiest season

119.6 in2007-08

Station Germantown Wastewater Utility (USC00473058), 870 ft elevation, 10.3 miles from the population centre. Daily records from 1944 to October 18, 2026; 98.4% 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 USC00473058.
• 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.