August 1
- 1674 – A tornado or series of tornadoes embedded in a squall line struck Utrecht in the Netherlands, causing major damage to numerous homes and destroying four churches.
August 2
- 1967 – A small tornado outbreak, starting on August 1, hit the Upper Midwest, resulting in mostly brief touchdowns. An early morning F3 tornado destroyed cottages near Lake Mendota in Wisconsin. Two people were thrown into the lake and killed. Five others were injured.
August 3
- 1885 – A tornado outbreak struck the Mid-Atlantic states. An F2 tornado struck portions of Philadelphia and Camden, New Jersey, killing 6 people and injuring 58.
- 2008 – Tornadoes touched down across Germany, the Netherlands, and France. An F4 tornado severely damaged or destroyed numerous homes and apartments in Hautmont, France, killing 3 people and injuring 18.
- 2018 – An EF4 tornado hit Alonsa, Manitoba, Canada, killing one person and injuring two others. This was the only violent (F4/EF4 or F5/EF5) tornado recorded in 2018, marking the first year that no violent tornadoes were recorded in the United States. It was also the first violent tornado to hit Canada since the Elie, Manitoba tornado of 2007.
August 4
- 2020 – Tornadoes spawned by Hurricane Isaias touched down along the East Coast of the United States. An EF3 tornado destroyed a mobile home park near Windsor, North Carolina, killing 2 people and injuring 11.
August 5
- 1843 – A tornado outbreak hit the Mid-Atlantic States. One tornado caused significant damage in Bethel Township, Pennsylvania and another struck near Philadelphia.
August 6
- 1879 – The easternmost significant tornado on record in North America struck Bouctouche, New Brunswick, killing five to eight people and injuring ten. About 80 homes and a church were destroyed. It was estimated at F3 intensity.
- 1969 – A major tornado outbreak hit Minnesota, resulting in 15 deaths and 109 injuries. Most of the casualties were from an F4 tornado that killed 12 people and injured 70 in Outing and along the shores of Roosevelt Lake. An F3 tornado killed two people in a cabin near Two Harbors and another killed one person near Jacobson.
- 1993 – Part of a larger outbreak across Virginia and North Carolina, an F4 tornado caused major damage in Petersburg and Colonial Heights, Virginia, killing four people and injuring 246. Three people were killed and nearly 200 were injured in the destruction of a Walmart in Colonial Heights. Damage from this tornado totaled $46.7 million. This was one of only two F4 tornadoes on record in Virginia.
August 7
- 1924 – Strong tornadoes touched down in the Wisconsin and Nebraska. An F4 tornado hit Northfield and Black River Falls, Wisconsin, killing 4 people and injuring 20; homes were swept away in Black River Falls. Another F4 tornado killed 3 people and injured 60 in and near Bloomer, Wisconsin, with debris carried up to 20 miles (32 km). One person was killed and another was injured when an F3 tornado destroyed a farm house near Rushville, Nebraska.
- 2003 – A weak but destructive F1 tornado hit a trailer park in Riviera Beach, Florida, destroying 58 homes and damaging 171. Twenty-eight people sustained minor injuries. Damage totaled $70-80 million.
August 8
- 1939 – A significant tornado outbreak hit Michigan. An F4 tornado moved through Kalamazoo, killing two people, and destroyed 25 homes in Comstock. Seventy-five people were injured. A strong F3 tornado injured six people in Kent City. Two F2 tornadoes injured a total of eight people near Midland and along a lake near Lapeer.
August 9
- 1878 – An F4 tornado moved through Wallingford, Durham, and Killingworth, Connecticut, killing 34 people. Debris was carried up to 65 mi (105 km). The aftermath became a tourist attraction, drawing 22,000 visitors two days later.
- 1969 – An F3 tornado tore through the suburbs of Cincinnati, killing four people and injuring 147. Twenty-Seven homes were destroyed, 200 sustained major damage, and 2,300 sustained minor damage. A large motel and an apartment complex were also heavily damaged. In all, about 1,500 people lost their homes. Damage totaled $15 million, equivalent to $96 million in 2023.
August 10
- 1924 – An F4 tornado destroyed a farm near Thurman, Colorado, killing 10 people. The home had been hosting Mennonite services when several funnel clouds and tornadoes developed nearby. The men left to provide assistance, but found no damage. They witnessed the destruction of the home on their return.
- 2011 – A rare event for August, an EF2 tornado destroyed two mobile homes in Locust Grove, Oklahoma, killing one person and injuring two others. This was only the fourth strong (F/EF2 or stronger) tornado to hit eastern Oklahoma in August since official records began in 1950.
August 11
- 1969 – An F1 tornado tornado hit Wisconsin State Fair Park in Milwaukee, resulting in the collapse of three large tents and injuring between 146 and 153 people.
- 1999 – A strong F2 tornado tore through downtown Salt Lake City, killing one person, injuring 70, and causing $170 million in damage. About 300 homes were damaged, with some left uninhabitable. This was only the second killer tornado in Utah's history; the first was in 1884.
August 12
- 2002 – A tornado of at least F3 intensity struck Făcăeni in southeastern Romania, killing three people, destroying 33 homes, and damaging 395. This was the first strong tornado to be documented on the new Romanian Doppler radar system and marked the beginning of efforts to forecast tornadoes in Romania.
- 2005 – An F2 tornado moved through a trailer park in Wright, Wyoming, damaging 120 of the 250 homes in it, of which 91 were destroyed. Two people were killed and thirteen were injured.
August 13
- 1943 – A tornado outbreak impacted northern Ohio. The worst damage was from an F3 tornado that moved through or near Canton, Genoa, Reedurban, and West Manor, killing one person and injuring 34. Another F3 tornado killed one person and injured 28 in Leavitsburg. A third fatality occurred when an F3 tornado came ashore from Lake Erie and hit Vermillion
August 14
- 1898 – An F4 tornado destroyed farms between Clear Lake and Gary, South Dakota, killing eight people. Five members of one family, along with two laborers, were killed on one farm. Another farm was completely obliterated.
- 1971 – A tornado moved through Kin Kin, Queensland, Australia, destroying several homes and killing three people. This was the deadliest tornado on record in Australia.
August 15
- 1787 – The largest known tornado outbreak of at the time, the Four-State Tornado Swarm produced tornadoes across Connecticut, Rhode Island, Massachusetts, and New Hampshire. Two people were killed, and ten were injured, by a tornado in Wethersfield, Connecticut, where the "black column whirled with amazing velocity and a most tremendous roar." One tornado moved across parts of three states from near Killingly, Connecticut to Gloucester, Massachusetts, cutting across Rhode Island.
- 2008 – A significant tornado outbreak hit southern Poland. An F3 (T6) tornado killed two people in Rusinowice and Kalina and injured 40 others. About 800 structures were damaged. An strong F3 (T7) tornado caused major damage in Sieroniowice, destroying thick brick walls and injuring 15 people.
August 16
- 1888 – Quebec's deadliest tornado hit Salaberry-de-Valleyfield, killing nine people and injuring fourteen.
- 1994 – A tornado outbreak hit the Southeastern United States with the most tornadoes touching down in South Carolina. An F3 tornado caused major damage in Lexington, South Carolina, injuring 40 people.
August 17
- 1946 – An F4 tornado killed 11 people and injured 100 in the destruction of a campground near Mankato, Minnesota. Farms were also destroyed, resulting in the deaths of more than 1,000 turkeys. An F4 tornado leveled a farm house and struck Wells, Minnesota at F2 intensity, injuring 30 people.
August 18
- 2005 – A tornado outbreak affected the Upper Midwest with all but one of the tornadoes touching down in Wisconsin. The strongest of these, rated high-end F3, hit Stoughton, killing one person and injuring 23. Homes were leveled in F4 fashion, but they were not well-constructed and the tornado was slow moving, allowing extra time for its winds to cause damage.
August 19
- 1845 – One of the few known F5 tornadoes outside the United States struck Montville, Seine-Maritime, France, killing 75 people and injuring 130. Three new, solidly-built mills were completely destroyed, trees were carried great distances, and debris was found 20 miles (30 km) away.
- 1890 – Several strong tornadoes touched down in Pennsylvania. An F3 tornado tore through the north side of Wilkes-Barre, destroying 400 buildings, killing 16 people, and injuring 60. An F2 tornado killed three people in Luzerne County, and an F3 tornado killed two people near in Susquehenna County.
August 20
- 1928 – A tornado outbreak resulted in nine deaths across the Upper Midwest. An F4 tornado moved through Austin, Minnesota and caused near-F5 damage to a farm near Glenville, killing six people and injuring 60. Five died in Austin. An F3 tornado killed two people in Twin Lakes, Iowa, where debris from destroyed cottages reportedly filled the eponymous lakes. Another F4 tornado killed an infant on a farm near Ellsworth, Iowa.
- 1970 – An F3 tornado struck Sudbury, Ontario, with little warning, killing six people and causing CAD $17 million in damage. Weather authorities were initially reluctant to classify this event as a tornado.
- 2009 – A tornado outbreak produced 19 tornadoes across southern Ontario. An F2 tornado killed a child in Durham and injured several other people. Two F2 tornadoes (one of them possibly F3) hit Vaughan, damaging over 600 homes.
August 21
- 1521 – The earliest documented tornado in the Americas struck Tlatelolco near Tenochtitlan, now Mexico City, during the final days of the Fall of Tenochtitlan.
- 1883 – A devastating F5 tornado hit Rochester, Minnesota, killing at least 37. Many others were seriously injured and may have died later. More than 135 homes in Rochester were destroyed and at least 10 farms outside of town were leveled.
- 1918 – An F4 tornado destroyed much of Tyler, Minnesota, killing 36 people, and damaging or destroying about 600 homes and businesses.
August 22
- 1851 – A tornado moved through Arlington, Medford, and Malden near Boston, Massachusetts, destroying well-built homes and injuring six people.
- 1964 – A tornado outbreak hit the Midwestern United States. An F4 tornado hit Port Washington, Wisconsin, injuring 30 people. The tornado mostly moved a treetop level, but destroyed homes where it fully touched down. A house was split in two while a baby sleeping inside was left undisturbed.
August 23
- 1956 – Three tornadoes touched down in the Chicago area. An F2 tornado in Tinley Park injured three people and tore the roofs from 11 homes. Three others were injured by an F1 tornado in St. Charles and another F2 tornado hit Elgin.
- 1968 – An unusual northwest-moving F3 tornado moved through Courtenay, North Dakota, damaging several homes, one of which was leveled, and tearing the roof from the school gymnasium. Three people were injured.
August 24
- 2006 – A small but significant tornado outbreak hit the Upper Midwest. An F3 tornado touched down in Nicollet, Minnesota and moved across the north side of Kasota, killing one person and injuring 37. About 100 homes in Kasota were damaged with three of them leveled.
- 2016 – Despite a low forecast probability of tornadoes, an outbreak produces several significant tornadoes in the Midwestern United States and southern Ontario. An EF3 tornado hit Kokomo, Indiana, destroying 80 homes, damaging 1,000 others, and injuring 20 people.
August 25
- 1814 – A tornado, possibly spawned by a hurricane, hit Washington D.C. during the burning of Washington, lifting cannons and likely killing British troops. This tornado, and the storm that produced it, may have contributed to the British retreat.
- 1948 – A tornado moved through Frankton and Hamilton, New Zealand, killing three people and injuring 80. About 150 buildings were damaged or destroyed. This was the costliest tornado on record in New Zealand and is tied with the 2012 Aukland tornado as the country's deadliest.
August 26
- 2007 – An EF4 tornado struck Northwood, North Dakota, killing one person and injuring nineteen. About 90% of the buildings in town were damaged. A section of a trailer park was destroyed and cars were mangled beyond recognition at a dealership.
August 27
- 1854 – A tornado moved across Louisville, Kentucky, killing at least 25 people and injuring at least 100. The worst casualties were at a newly-built church, were at least 18 of the 55 people present were killed. Others may have died later from their injuries. An orphanage, school, and hemp factory were also destroyed.
- 1945 – An F3 tornado spawned 60 miles from the eyewall of the 1945 Texas hurricane moved across the north edge of Houston, killing one person and injuring 12. Several homes were swept away, but most had been evacuated ahead of the hurricane.
- 1964 – An F2 tornado on an erratic path hit a village in the San Xavier Indian Reservation near Tucson, Arizona, killing two people and injuring nine. These were the first recorded tornado fatalities in Arizona.
August 28
- 1884 – An F4 tornado moved across Sanborn, Miner, and Hanson Counties, South Dakota, killing one person. This tornado was photographed near Forestburg in what is widely reported as the first ever photo of a tornado. However, another tornado was photographed earlier that year near Garnett, Kansas.
- 1973 – An F4 tornado touched down near Canaan, New York and moved into West Stockbridge, Massachusetts, killing four people. Three of the deaths were in the destruction of a large truck stop, where fully-loaded semi trailers were rolled and a car was found 20 feet (6 m) up a tree.
- 1990 – A devastating F5 tornado hit Plainfield, Illinois, killing 29 people and injuring more than 350. Ted Fujita assigned an F5 damaged based on severe ground scouring and extreme damage to vegetation. Three people died at Plainview High School one day before classes were scheduled to start.
August 29
- 1910 – An F2 (possibly F3) tornado destroyed a large portion of Heaton, North Dakota, killing two people. A house was reported carried 300 feet (90 m) while ten people inside were uninjured.
- 1992 – An F3 tornado struck Wautoma, Wisconsin, destroying 48 homes and damaging about 400. with damage costing $10 million. One person was killed when here trailer home was thrown several hundred feet, and 30 others were injured.
- 2005 – Hurricane Katrina made landfall on the United States Gulf Coast, resulting in the most active phase of its associated tornado outbreak as 39 tornadoes touched down. An F2 tornado killed one person and approximately one million chickens, along with other livestock, near Glenloch, Georgia.
August 30
- 1971 – An F2 tornado hit Tempe and Mesa, Arizona in the Phoenix Metropolitan Area, destroying several homes and causing significant damage to others. Forty-one people were injured, mostly from flying glass.
- 1974 – A series of tornadoes touched down in the vicinity of Great Bend, Kansas, which mostly remained over open country. One large tornado was captured on film near Ash Valley in some of the best-known tornado footage of the twentieth century. While this tornado only produced F1 damage, analysis of the film indicated winds in the F2 range near the ground and in the F3 range aloft.
August 31
- 1977 – An F4 tornado moved across the Wausau Metropolitan Area in Wisconsin, injuring 10 people. It moved at treetop level in Wausau and caused its worst damage in Rib Mountain, where 15 homes were destroyed. There was damage to 60 farms.